Monday, July 15, 2013

Fantastic Frontiers: Encounter Mechanics

So you're wandering along in the forest, and there's a dice check for a random encounter. It tells you to roll on a table. The table coughs out a mature red dragon. You're traveling with two halfling slingers and a spoony bard, and dragons are out of your league. What are your options?

This kind of problem is one of those balance vs verisimilitude issues that has mostly been resolved in favor of downgrading the concern with simulationist ideals. There are a few totally contrived and artificial solutions for dealing with the game-breaking un-fun of getting eaten by the dragon on the first day out of town. You can usually find one of the following in any game that you'll pull of the shelf that involves any kind of random/procedural aspect to encounter generation:
  1. Functional Immortality: This amounts to just scaling down the consequences of death. You don't die, you just get knocked unconscious for a turn and maybe lose some recoverable resources. This is the approach taken by MMORPGs and also by casual boardgames like Runebound.
  2. Relative Challenge Levels: I discussed this a couple posts ago, and it's most common in pencil and paper RPGs where narrative dominates. In this approach, dragons don't appear until you're strong enough to want them to appear, and the kind of dragons you eventually find will always be a bit above or below your current capabilities.
  3. Perfect Information: Or maybe not perfect, but good enough. In this approach, the difficulty of the encounter is generated in advance ("red" vs "yellow" vs "green"), so you can know roughly what's in the room (or wilderness hex) before you enter. Procedural elements like tables or random cards are only used to provide flavor or a small variation of the predicted difficulty.
  4. Encounter Repellant: Anything that reduces the chance of finding trouble. The least artificial way to accomplish this is to introduce a skill ("Survival" or whatever) that slowly turns off encounters that aren't wanted, and for a totally procedural game system, turns on the encounters that are. Depending on how important random encounters are, this might become a mandatory skill that everyone needs to take, which just provides a narrative gloss for using the relative CL approach.
I'm trying to avoid all of the above, since it results in an environment that doesn't feel as unforgiving as I think a true wilderness should. I do intend to include some rumors or tavern tales to provide a few informational leads that might generate encounters ("The Aztecs are hiding their gold in a village in the hills 20 miles to the north!"), but this is mostly to create an incentive to start wandering and get into all manner of other trouble. Here's a list of my intended alternative approaches:
  1. A Scouting Contingent: In FF, you'll be able to break up your expedition into two mobile groups, a recon group and a main body. There aren't any real restrictions on the groups, except that they need to stay within a certain distance of one another to remain within communication range. The intended use is that the recon group will be light and fast (light cavalry, say), or small and sneaky ("Send our hobbit!"), and scope out anything challenging in advance. This provides information, but at a potential price of putting the group at risk. A larger recon group is less fragile and can handle certain challenges without having to radio back to HQ for the big guns, but is also less stealthy and stakes more lost resources if it does go down. (BTW, the encounter table for entering a brand new hex is rather nastier than the random one while resting, so the main body will usually be able to provide for its own security if it doesn't get lazy or stingy.)
  2. The "Three Exit Ramps": Aside from some smoothing out of lumpy mechanics, I've imported the entire machinery of zero-edition encounter resolution from Underworld and Wilderness Adventures. That means that each encounter gets a surprise check, an evasion check (if surprise didn't help), and a reaction check (if evasion didn't help). Surprise determines who notices whom first; spot the dragon first, and you get to withdraw without incident (other way around, and it's trouble!) Evasion determines whether you can slip away even after being noticed, using speed and mobile concealment; if you're on horses, or in a dense forest, you can probably give that dragon the slip. Reaction determines whether something decides to chase you if you run, or else you can talk your way out of it using flattery or wits when caught; in a board game this is abstracted by dice rolls, but you can imagine this amounting to challenging the dragon to the venerable riddle game like Mr Bilbo. Even if each of these options only has (something like) an overall 1-in-2 chance of succeeding, the cumulative effect of getting to try each exit ramp in succession is that a lot of dice need to work against you before the dragon starts chewing off your face. Plus, there's a natural tension that comes from seeing all those attempts sequentially fail!
  3. Heroic Sacrifice: This is the last-ditch defense of a desperate leader, and will only be possible if you've configured your leadership party with enough valiant heroes to be willing to cover the escape of the rest of your expedition. The morale box system requires a certain number of expedition members to be committed to the fight (equal to the scale), but the rest can be dropped down into the reserve box, to represent their intentional decision to flee the battle. This works great against that lone balrog on the bridge of Khazad-dum dragon, but would be much harder to pull off against a horde of goblins who presumably can themselves split into groups and follow you. So it's not 100% reliable. Fortunately, evasion and surprise will already tend to work well against those larger groups.
Obviously all of this just adds up to "most of the time you can flee a bad encounter, but every once in a great while it still eats you". But the mechanisms by which this results are (1) strongly motivated by narrative gloss, and (2) likely to enforce various other negative results and complications in the process. Most importantly, you've now established a location where a dragon might live -- most encounters are persistent, though there's a confirmation check when you return to see if they've moved on -- so you can come back later to investigate with a larger team of crack archers and celebrated heroes in the future, to avenge the previous calamity. This makes the game feel less like it's holding your hand, and more like it's trying to kill you.

Sunday, July 14, 2013

MEK OP Game Night: Pathfinder One-Off

OOTS #819 says we're missing a bard
The rest of the summer is likely to be too busy to play anything (we're heading to Alaska on Tuesday for a two-week vacation), so instead of continuing the Guadalcanal campaign, we ran an intro session of Paizo's Pathfinder based on the Free RPG Day module Master of the Fallen Tower. I had some familiarity with Pathfinder -- well, really, I had seen D&D 3.5 as implemented in Neverwinter Nights, but the rules overlap is substantial -- but never actually played through a pencil and paper session. It was the first time my wife had ever seen a (non-computer) RPG, so she was a little nervous and intimidated. Naturally, we put her in plate mail and stuck her out front. (Toss the babies in the deep end of the pool. It's the only way they'll learn!) Three other players added up to the classic quartet: rogue (me), evocation wizard (Kyle), and cleric (Kim). We got through about six encounters, with the last two levels of the tower being compressed into a single boss battle.

Things went smoothly until the last fight, to the point where I felt moderately sorry for the locals who served as speedbumps. A spider was unceremoniously yanked off the ceiling with a grappling hook. A number of troglodytes were dispatched with a minimal number of axe strokes. A shocker lizard got eaten by crossbow damage, and crawled through the door half-dead to be beaten to death by multiple quarterstaff blows. Really, the worst part of the lower levels was taking a javelin in the throat.

Things turned south in a hurry at the top. A couple of bonus troggs had been added to the final battle, beyond the written version of the scenario, and the boss's pet albino crocodile scrambled across the floor to savage me with a single maceration. This set up an extended comedy of errors where no one could hit any of the trogs, while the leader (a druidic sort of a troglodyte) sent a carpet of spiders roaming around the room to writhe all over everyone with their crawly legs for minor amounts of damage and moderate levels of the heebie-jeebies.

Pretty much everyone ended up dead at some point during the fight, and Kim's cleric was ignominiously forced to use some sort of AoE healing ability to heal up the crocodile along with the rest of us. There were several points where any logical person would have gone screaming back down the stairs, but we're adventurers, and so dying repeatedly for the sake of a few dozen gold pieces must seem like a sensible application of cost benefit analysis to people like us. Amazingly enough, everyone lived.

Result: Lots of loot that we'll never use, since it was a one-off. Also, the pride that comes from getting our names on little museum-plaques somewhere in the PFRPG official gameworld setting. Or maybe we all ran to the stinky troglodyte throne at the same time, and the structurally unstable tower collapsed and killed us all, in dramatic fulfillment of the exposition textblock.

Here's the roster right before Princess Leia came out to award medals to everyone who wasn't a wookiee or a droid:

That's a female dwarf, BTW. Pink ribbons in the beard, that's how you tell.
A few thoughts on the Pathfinder game system:
  1. If games were anything like the tech industry, Paizo would get bought up by WotC and rebranded back to being D&D 4.0, which is basically the role it's already filling.
  2. The thought that a game with a 500+ page rule book is the market leader is pretty amazing. The art probably helps, but that's still an amazing imposition on modern attention spans. I wonder if adding more midriff-baring elvish sorceresses to the next edition of Giancoli would convince my students to actually read the thing? (Answer: Yes, but only for a tiny subset of the class, all of whom already have A's.)
  3. I really miss being able to backstab. Yeah, sneak attack works more often, without the need for stealth, and is basically the same effect (well, +2 to hit instead of +4), but it somehow seemed cooler when it was harder to set up and pull off.
  4. It's eye-popping how much healing clerics put out in this system. In the old days, there really weren't any AoE heals until something like 7th level. Here a cleric can pump them out multiple times in a game session, with a sort of innate ability that replaces the old Turn Undead. This makes any low-level party with a cleric much more survivable than the equivalent team in 1st or 2nd edition. Even so, the last battle was a nail-biter, despite (what I suspect was) some on-the-fly nerfing of the druid's spell list.
  5. Doing a stand-alone module like this feels more tense than playing in a linked campaign like the last one I did (JMO's Aromathus: 711 CE). The sparseness of the narrative makes it feel less likely that the party will be getting ushered past the tough fights by generous allotments of plot armor. I remember thinking in college that things felt less exciting than when I was younger and playing the old basic modules, and wondering if it was just rose-tinted hindsight. But I think it was a more a matter of higher lethality being part of the expectations for the isolated modular adventures everyone played back before the Hickman revolution.
  6. My wife this morning: "I woke up with the lyrics to Roll a D6 stuck in my head. Well, really only that one line, since I can't remember any of the others." I guess that means she had fun, right?
  7. This is further rekindling my desire to create some kind of persistent strategy-RPG living fantasy world, so that the survivors of a little session like this can pack away their loot to resurface as hired mercenaries and battalion captains in some large-scale battles.

Friday, July 12, 2013

Craft Project: Stackable Terrain Hexes

For a while I've wanted my own set of stackable terrain hexes, like the ones in the now-discontinued Heroscape line. These can be useful not just for my own design purposes, but for any hex-based miniature or RPG system that involves the procedural generation of new terrain features. The ability to lay new terrain tile by tile is valuable for an exploration-based game, since it helps create that fog-of-war effect that makes 4x games like Civilization so addicting.

I have no idea how to make interlocking edges, but I think that the density of porcelain tile is sufficient to keep them from sliding around too much. I used this direct supply website (a bit nervously given the suspiciously low price!) and ended up with a decent collection of tiles. Then I printed terrain from the same default terrain set I used to create the map I posted previously, which is available with the free version of Hexographer. After cutting and pasting, this was the result:

Greek letters, since that's how I roll.
The green tiles are too dark for good contrast, but all the others look great. In hindsight, I should have used something less mountainous for the hills, but I'm too lazy to redo them all.

I've tossed on some star-shaped wood counters from Hobby Lobby, which I use to mark the locations of settlements, ruin sites, and encounters. The tiles are laid on a felt Hotz Mat, which does a good job of keeping the rough side of the tiles from sliding around. Another alternative, for a more portable map, would be to back the paper tiles themselves directly with more felt. Sort of like the old flannelgraphs from Sunday school, but with fewer apostles and more necromancers!

Thursday, July 11, 2013

The Encounter Triad

In Magic Realm -- which I keep revisiting as the ur-type of exploration adventure games -- you'll find a bunch of standard fantasy archetypes like a dwarf, a wizard, a knight, and so forth. But there are also unconventional play options like a captain(?) and a pilgrim(?!) that would raise the eyebrows of a modern player. These guys don't make sense in the modern concept of a pseudo-RPG, because they're really not capable of winning most fights. They just wander around the board, sneaking past enemies and grabbing unguarded treasures. You can find a modern reviewer here who seems totally baffled by this play element, a flaw in what he obviously regards as an otherwise classic game.

What's happened between 1979 and 2013 is an alteration of the social contract of the game. In the 1970s, a central feature of what we now call "encounters" was the sorting operation of each encounter into three possible responses: fight, run, or talk. Being a good player meant being able to skillfully classify each encounter into one of the categories. Intentionally fighting something that necessitated a "talk" reaction or a "run" reaction was a failure of the player to play the game skillfully. A game that created penalties for neglecting to respect the triad was a good design.

A modern player coming into contact with this philosophy for the first time will be baffled by why (for example) the first edition of D&D used extraneous dump stats like intelligence and charisma to determine things like "known languages" and "reaction bonus", instead of doling out sexy combat bonuses. Or why the encounter tables had entries like "4d100 kobolds" without evincing the least concern about what your first-level cleric was going to do after bumping into 213 of the yappy little critters just a few miles outside the Keep on the Borderlands.

Today, 30 years later, the triad is mostly forgotten. Instead, the new social contract is that "fight" should always be an acceptable response, and that any attempt of the game to punish a decision to fight is a failure of game design. The ideal of game balance (which keeps an entire division of Blizzard employees working around the clock) requires that every player make a totally equal contribution to combat. If you said something like "my character's special talent is running away from fights", that would be a punchline to a joke. The turning point might have been the Roper encounter in the Sunless Citadel, where WotC tried to launch their 3rd edition with a module that featured an encounter that was totally unbeatable for a first-level party and suffered a broad backlash from the player base.

Let's think for a moment about avoiding a hostile encounter. Here's the original evasion table from TSR's Underworld and Wilderness Adventures, published in 1974.
This table is important for two reasons. First, it implements what I call a quadratic vs. linear scaling law. Note the size categories rise in a roughly quadratic manner, with bounding brackets that include values like 1, 4, 9, and 25. (Mysteriously missing: 16!) Size has a sublinear effect on evasion, with the decline in evasion chance falling roughly as the square root of the party size. This is a design element that would never pass muster today, where asking players to either (1) use a big table with ugly formatting, or (2) perform a square root operation. This would never make it past playtesting in today's math-phobic world. It's a compact example of diminishing returns, however, and so I've been using linear/quadratic scaling for my own design purposes whenever possible.

More importantly, though, it implements a sort of self-balancing procedure in the game. Early in the game, when you have a small scouting group, you'll have an easy time dodging goblin patrols. The more goblins in the patrol, the easier they'll be to dodge. As your group grows, you'll have a harder time avoiding their notice, and even some of the large warbands will start to chase you around the map. This kind of mechanism creates a protective in-game feedback loop that has some logical rationale: It's hard for a small group to run from a big one. More importantly, it moves the responsibility for balancing combat off the shoulders of the designer (or, in an RPG, the GM), and onto the shoulders of the players. You want a fair fight? Just keep dodging the unfair ones until you find it.

This style of evasion table survived in the RPG world for another decade before falling out of use. As it began to disappear, the concept of challenge level replaced it -- the idea that encounters automatically scale to reset their difficulty relative to player capabilities. Instead of finding huge camps packed full of orcs that you need to carefully circumvent until you can raise an army to conquer them, the new paradigm is that those camps just don't exist until your party becomes powerful enough to need them to exist. That approach has its place. But it doesn't feel right for an exploration game on an open map, which is by nature at the extreme sandbox-ish end of the spectrum. An excessive amount of dynamic scaling in a sandbox will place the entire game on a treadmill (cf. the Oblivion syndrome). Treadmills are the antithesis of exploration.

This encourages me to take the table above and clean it up (using a nice universal formula) for the company-scale exploration game I want to make.

Wednesday, July 10, 2013

Fantastic Frontiers: Dice That Tell Stories

One of the appealing features of Avalon Hill's Magic Realm is that the combat system is based entirely on descriptive combat maneuver choices. In the basic game, there aren't any combat dice rolls beyond the ones that set enemy tactical choices. Instead, combat is just a mechanical implementation of different combat maneuvers that you select (or for foes, that the dice select). This makes it easy to have a battle that reads like a journalistic description of what really happened: "The dwarf ducked, and the thrust from the lancer's spear was too slow to intercept him, and then the giant crushed him with a club, but the helm shattered and absorbed the blow..." This is the actual description you'd give someone even standing outside the game universe, in contrast to a more abstract system where you'd say "I rolled an 11, which was sufficient to hit against an armor class of 13, and then I rolled a 5 on my damage."

Most wargames can't avoid the necessity of dice, and this means that to add this kind of flavor, the dice need to make a choice for you that translates into some interesting explanation for why you won or lost. The morale box system involves some extra work beyond just tallying all attack factors and rolling on an odds table, but it provides the benefit of both telling a story and creating some interesting tactical choices in combat. Let's walk through a full example of a complicated battle with lots of different troop types on each side, for the sake of explaining how everything works. This will take a while, but it's as useful for me as for anyone reading this!

Here's the scenario, which this time will be in a fantasy world. A team of explorers headed by a wizard (5th level mage) with two loyal companions (both 3rd level fighters) encounters a warband of orcs, trolls, and ogres. After some checks for details like surprise, reaction, and evasion, it looks like the monstrous raiders have decided to attack. This sets up the following order of battle:
  • Expedition forces defending
    • 5th level mage
    • 3rd level fighter (7 armor, +1 charisma bonus)
    • 3rd level fighter (9 armor, -1 charisma penalty)
    • 18 light footmen (leather/shield, 3 armor, 8 morale)
    • 4 heavy footmen (chain/shield, 5 armor, 8 morale)
    • 3 light horsemen (leather, 2 armor, 9 morale)
    • 2 heavy horsemen (plate, 6 armor, 10 morale)
    • 6 crossbowmen (chain, 4 armor, 8 morale)
    • 2 longbowmen (chain, 4 armor, 9 morale)
    • 8 noncombat hirelings (scouts, porters, etc) that need to be defended
  • Humanoid forces attacking 
    • 1 orc warlord (+2 charisma bonus when leading orcs)
    • 90 orcs (4 armor, 6 morale)
    • 2 ogres (4 hits, 5 armor, 10 morale)
    • 4 trolls (6 hits, 6 armor, 10 morale)
These values for armor and morale are taken from the 1991 Rules Cyclopedia (after flipping to ascending armor values), as an example of how it's pretty easy to just grab monsters for an encounter table from any standard d20 RPG monster collection.

Here's a list of the sequence of play for this battle
  1. Determine combat scale
  2. Populate morale boxes (first defender, then attacker)
  3. Roll 3d6 for tactical advantage
  4. Fire missile barrages, and apply casualties
  5. Fire artillery barrages, and apply casualties
  6. Roll a 2d6 morale check to determine which forces are included
  7. Apply melee casualties for each side based on included attackers

 

1. Scale

First, let's determine the size of each side. There are 46 combatants on the human side, and 97 for the monsters. But we might want to adjust a bit for some of the larger combatants. The ogres and trolls are about twice the size of an orc, so let's count them double and add another 6 to get 103.

The scale is determined by the smaller size, which creates the limitation on how many combatants can be in direct contact at once. The size of a single "unit" (really, more like a front rank of the formation) will be based on this smaller size. Let's assume the size of this unit is 20% of total size, or 2*46/10 = 9.2, rounding off to 9.  The fact that the monsters have a 2-to-1 advantage should count for something too. Let's take the size ratio (103/46)=2.2, and say that this provides an extra bonus of 2 to scale, to represent the ability of the larger force to wrap around the corners of the smaller force and get in a few extra attacks. This bonus is small here, but if one side outnumbered the other by 10-to-1 -- or 50-to-1(!) -- it could become much more important.

The scale for this battle will be 9+2=11. That means that the footmen and orcs, at minimum, will not all be able to attack at once because they must be organized in deeper formations with multiple ranks.

Formula: scale = (20% of smaller size) + (size ratio)

This is also the appropriate time for the mage to announce that he's going to cast a fireball spell, and for all the ranged units to announce that they're going to participate and spend ammunition. (If ammunition was missing, they'd still be available to fight in melee using daggers and such, but couldn't barrage.)

 

2. Morale boxes

Now we need to start to deploy forces onto the battleboard. The defenders go first. Each morale box can contain 3 types of troop: assault, infantry, and ranged. Assault troops are anything that can rush, flank, or break through a line, such as cavalry or large monsters. Ranged units are anything that can launch or throw projectiles. Infantry are anything else.

Each box can only contain one troop type from each of the three categories. Units can't go in a box higher than their morale, but might be forced into a lower box if the higher one is already occupied by something of the same category. All the assault and ranged troops are already in groups smaller than the scale, so they don't need to be broken down. The heavy horse can go into the 10-box, the light horse into the 9 box, the longbows into the 9 box, and the crossbows into the 8-box.

The infantry pose a greater problem. The 18 light footmen will need to break into two groups, one of 11 and one of 7. And both of those groups, along with the heavy footmen, are all in competition for the 8-box. The 11 light footmen would inflict the most damage, but the 4 heavy footmen would absorb damage more efficiently. Anticipating that the deaths of the ogres and trolls will substantially weaken the enemy forces, let's just try to kill them all off and put the 11 light footmen in the 8-box, the other 7 in the 7-box, and the heavy footmen in the 6-box.

Now we'll position leaders. Note that one of the fighters provides a +1 charisma bonus to morale. Adding this leader to the 11 light footmen will pull them one box higher. The other fighter has a -1 penalty. We could put him with the other fighter, so they'd both cancel out and the light footmen would stay in the 8-box. But look at they heavy horsemen! They're all alone in the 10-box, which seems a little risky. A roll of 11+ will include only them (in shaken condition), and they would fare poorly against a horde of orcs. Instead, let's put them under the command of the low-charisma fighter (assuming he has a horse of his own to ride). Now they have an effective charisma of 9. But that's fine, since it looks like a better idea to drop them back to the 8-box, to cover those 6 lonely crossbowmen left behind when the footmen moved up.

The mage is going to launch a Fireball. That's only safe if he's standing in front, since fireballs can't launch over friendly troops like a physical projectile. So he'll stand with the longbowmen in the 9-box. This is risky, since if only this box is included, his neck is on the line. But at least the front fighter is covering him.

Note that I'm not counting the leaders against the scale limit of 11. This is a special perk of leaders, which allows them to effectively stack together and eventually make an incredibly powerful strike force that can stand in front of the army and knock out deadly enemies like dragons that only a team of heroes can reasonably handle!

Here's what the defenders look like. Note that this is a pretty complicated army, and there's no reason why you couldn't use a simpler one, with only one troop type for each category. It's helpful to be balanced in all three categories, though, as von Clausewitz can explain.

As usual, I'm stealing the War of the Rings figures to use as leaders.
For the monsters, the choices are simpler. The trolls will take the 10-box. The ogres can't be in the same box as the trolls (both are assault type troops) so they fall back into the 9-box. It could be the other way around, but the trolls will hold out better against barrage attacks. The orcs will break down into groups of 11, and the leader will boost one of those groups up to morale 8. The others will start in box 6, and go down to 2. Note that there are 4 orcs left over, which have no chance to participate and get stuck in the reserve box for the whole battle to serve as spectators.

I'd like a larger battle board, so I can place minis for all the armies beside their numbers.
This set-up for the monsters is a bit risky, since there's some chance that the trolls and ogres will be caught by themselves without orcish support, if the orcs decide to hold back and just watch during the first round. It would be safer to move at least one of these groups down into the same box as the orcs. But trolls aren't known for caution, so let's leave them there.

 

3. Tactical Advantage

We roll 3d6 for the expedition. The result is a 13. That's good for a +1 advantage to the defenders, which translates into a -1 disadvantage for the orcs. This will be relevant when casualties are applied.

 

4. Missile Barrage

Now things turn hot. The 2 longbowmen and the 6 crossbowmen are going to try to fire at the lead enemy troops, which in this case are trolls. After deducting 8 units of ammunition from the expedition supplies, there are 8 attacks to be applied. Adding the trolls armor (6) to their disadvantage (-1) gives a conversion rate of 5. So the trolls suffer one wound. (It would take a full 10 attacks to create a second wound.) Bear in mind that each troll takes 6 wounds to kill! This is barely a scratch, given the toughness of troll hide.

 

5. Artillery Barrage

The mage here is the ace in the hole for the expedition. He's the "artillery" of a fantasy world. His fireball is at the 5th level, so it's going to do the equivalent of 5 attacks on each target. (Each point of damage represents a "hit dice" in RPG terms.) It's also going to hit up to 5 targets, which in this case just means all 4 of those trolls. Best of all, armor doesn't help against arcane fire. So the disadvantage of -1 simply implies that each troll takes 5 hits of damage, converting attacks to damage 1-to-1. One troll dies outright, thanks to the archers, and the others are in rough shape with one hit each.

 

6. Morale Check

Each side rolls 2d6 to see which troops are included. I roll an 8 for the expedition, which means that the 8- and 9-boxes are included. That's most of the army. The troops in the 6- and 7-boxes are shaken, which means they'll hold back from fighting, and they'll flee if a higher box containing the same troop type (infantry) is wiped out. That means that the expedition forces have 3+2+11+2 = 18 attack factors from their troops. (Crossbowmen can't attack, since they're reloading their crossbows and have no melee capability). The leaders also add another 3+3+1 = 7. The wizard can cast some additional spells using a spell point system (which I'll figure out later) to add additional random attacks. For now, let's just suppose he spends 10 points to roll 1d20, and gets a 14. The total is 18+7+14=39 attack factors to apply against the monsters.

The monsters roll a 4 (egads!) which means the expedition is probably in trouble. That's going to include nearly all of those orcs, except the 2- and 3-boxes and the reserves. That's 44 orcs plus their captain, for 45 attacks. Then the 3 surviving trolls will each add 6 (reflecting their superior hit dice), for a total of 18. Finally, the 2 ogres each add 4 (their hit dice) for a total of 8. The overall result is 45+18+8=71 attacks against the expedition.

 

7. Melee Casualties

Let's see what happens to the monsters, first. We start in the highest box, and work down. Assault troops die first, then infantry, and finally ranged. Killing all three of the nearly-dead trolls will take 3x5 hits, or 15 hits out of the 39 total, with 24 remaining. The trolls are down. Next up are the ogres. They have armor 4, so it takes 4-1=3 attacks to cause one wound. The remaining 24 attacks create 8 wounds, which is just enough to kill both of the 4 HD ogres. Only the orcs are left.

Casualties are simultaneous, so the 71 attacks are still going to hit the expedition. First up are the assault troops in the 9 box, those 3 light horsemen. The cavalry have armor 2, and with the +1 advantage, it will take 3 attacks to drop them. They go down, at a cost of 9 attacks, leaving 62.

Next up are the 11 light footmen. They have armor 3, so it will take 3+1=4 attacks to kill each of them. They go down for 44 hits, leaving 18 still remaining.

Their captain is that 3rd level fighter with the 7 armor. It takes 7+1=8 attacks to cause him one wound, so he takes 2 wounds for 16 attacks, and the final 2 attacks are wasted. He's still holding on, with 1 hit.

The more compact expedition forces still have the upper hand, unless the orcs roll well again.
At this point the expedition can either continue the fight for another full round, or flee. If fighting continues, the remaining armies can be shifted around into new boxes, presumably with the wounded fighter being moved to the back ranks where he'll be safer. Any attempted escape will require a check on the pursuit-and-evasion table.

 

Assessment

This went roughly for the expedition, but the wizard and his fighter companions are still alive due to the prudent decision to move the light infantry up into the 9-box, to cover the wizard. Having the wizard that far forward was pretty risky, but with the trolls dead, it's now quite possible for the remaining expedition forces to beat back the orcs. Most of the orcs are in low boxes, and the roll of 4 might have been a lucky fluke that won't be repeated.

For sake of comparison, let's think about what would have happened if the monsters had rolled an 11 instead of a 4. Then none of them would have been included, and all the monsters would have been "shaken". The expedition forces would just get to pick any number of boxes (starting from the high end) to attack, and would probably have only included the trolls. The trolls would counterattack out of necessity -- but only at half-strength, since being "shaken" effectively halves that box's attack value. After half the trolls (2, in this case) were killed, the others would have run away, since being shaken also has this effect. And once the trolls ran off, the ogres below them would also have run off, since they're shaken and they're weaker than the trolls (only 8 attack value, versus 24)! But now the orc-filled boxes have no one in front of them, and they're weaker than the trolls too! The entire battle would have become a complete rout, and the trolls would have inflicted minimal damage of 12, just enough to drop the front group of 3 cavalry. Totally different battle!

Alternatively, suppose that the expedition forces had rolled a 10 or something. Now the crossbows aren't included, which means the first troll doesn't take a hit, which means that all four trolls reach melee. That means that the fighter suffers an extra 8 attacks, and dies. It also means that the expedition does much less damage, and most of the ogres are still facing them. In an absolute worst-case scenario, if the two lowest orc-boxes were also included, the entire 9-box might have been crushed, including the wizard. Putting a fragile spellcaster so close to the front of the line is risky, and a more cautious player might have skipped the Fireball option entirely -- but then those four armored trolls are like an iron wall! Decisions, decisions.

You can see how this kind of system doesn't just give the result of the battle, but also explains why that result occurred. The dice tell a story. In this case, it's a story about how the expedition was suddenly rushed by a shock force of trolls and ogres, and only their front line was able to form up and present a defense. They just barely managed to beat down the rampaging monsters with the help of some powerful pyrotechnics. But as they were weakened, secondary waves of orcs began picking off stragglers in the confusion. A hero was badly wounded, and his entire squad was wiped out to the last man! They stopped just short of reaching a wizard, who conjured powerful magic to force them to fall back.

This is intentionally a complicated battle, and most real battles in the FF system would be much simpler, more along the lines of "you have 2-3 troop types, and a half-dozen wyverns attack you". That would take much less set-up, although there are still a few strategic decisions that would be commonplace, such as whether to send cavalry far out in front, where it might die alone, or whether to keep all your forces in tighter formation, at the risk of eroding your army's morale by excessive caution.

Despite the lengthy explanation, this entire battle would take about 10 minutes to resolve, with five minutes to do the positioning in boxes, and most of the rest to do the necessary math for casualties. I didn't need a calculator at any point, just scratch paper, but one might be handy for the division involved in calculating the odds ratio bonus to the scale.

 

One final thought

This system makes armor very powerful, even small amounts of armor. Just a single shield can effectively make an infantryman twice as hard to kill. That's rather different in feel from an RPG system, where leather armor is usually in the "why even bother?" category. If you wanted to recover the same results as a detailed RPG battle, it would probably be better to scale back the value of armor, and divide everything by 2. For example, it might take a (2+2)/2 = 4 / 2 = 2 result just to get even a 2-to-1 ratio, which means that leather armor would be worthless without a 3d6 tactical advantage of at least +2 -- pretty rare! This would make combat more like an RPG, but also less able to describe the extreme case of something like the Conquistadors' absolute dominance over Mesoamerican technology.

Personally, I rather like the idea of having low-end armor varieties feel more useful, so I regard this as a feature and not a bug. It seems to me that the 1 point of armor supposedly provided by a shield should be more like something that doubles the survivability of an unarmored soldier, as opposed to something that just makes his chances of being hit slide from 50% to 45% like a d20 to-hit system would suggest. But your mileage may vary!

Tuesday, July 9, 2013

Fantastic Frontiers: Tactical Advantage

The previous post was about figuring out who bothers to show up to fight a battle. That's only half the story. The other half of the story is figuring out who survives until the end of the engagement. Military historian Richard Gabriel, author of Man and Wound in the Ancient World, writes:
In most battles of antiquity, a victorious army could expect to suffer approximately 5.5% killed in action, and 6% wounded, or approximately 12% of its force. A defeated army could expect to suffer horrendous casualty rates of approximately 37% killed and 35% wounded. These levels of dead and wounded were inflicted usually after the battle formations were broken and the enemy was surrounded or caught in the pursuit. (from Scipio Africanus: Rome's Greatest General)
That's a very "swingy" result to model in a game!

But even this doesn't adequately reflect what happens during an Age of Discovery between early-modern explorers with muskets and bronze age tribal warriors with clubs. If we accept that Cortes had a force of 400+ rondeleros fighting for the better part of four hours against a continuous stream of Tlascallans, then even a modest rate of one attack eliminated every five minutes per Spanish soldier gives a total casualty tally of 4*12*400 = 18,200. (Of course, a lot of these "casualties" were probably not kills, but enemy warriors who lost their nerve at the sight of horses and guns and ran away. That's already covered by the morale check system.) This would be against the recorded outcome of about 60 casualties (mostly wounded and with only a few immediate deaths) on the Spanish side. In other words, the ratio of casualties is about 300 to 1 in favor of the high-tech side!

The difference here probably had less to do with firearms, since matchlocks were slow to reload and Cortes only had a dozen of them anyway. The critical difference was steel. Europe had gone through several iterations of armor-piercing technology, and by this point Toledo steel was proofed to the point of being able to withstand crossbow bolts and musket balls. Stone age weapons like obsidian-studded clubs could do little more than hack at the exposed lower legs of a swordsman. Despite the common assumption that the age of armor dominance was in the high middle ages, this later period of primitive firearms actually represented the apex of enthusiasm for heavy 50 lb plate armor.

So the casualty system really needs to meet two criteria:
  • generate huge disparities in casualty rates when appropriate
  • give a hefty advantage to superior armor
Small marginal RPG-like differences like 5% bonuses to hit just aren't going to cover this kind of asymmetry. Instead, we need an almost logarithmic scaling to combat results.

The bottom-line number that's important here is the ratio of attackers to casualties. We need a dice roll to generate this number directly, for both sides. Here's a familiar-looking 3d6 bell curve table for RPG statistics:


Let's reinterpret this as giving the multiplicative ratio for attackers to casualties. When your army is attacked, roll 3d6 and look at the table. A result of +3 means that for every 3 attackers, you take 1 casualty. A result of -3 means that for every 1 attacker, you take 3 casualties. You can see that with this interpretation, the most common results of +1, 0, or -1 are all pretty much the same thing, an easy 1:1 ratio. (Presumably each side will be making its own roll, or better yet, the results are anticorrelated so that a +3 for one side is a -3 for the other.)

But now let's factor in armor. Let's say that some of your force is outfitted in plate mail and a shield, which my old RPG intuitions tell me should have an armor value of 7. With a dice result of +3, this now results in a ratio of 10 attackers to 1 casualty. Even with the worst result of -3, the ratio is still 4 attackers to 1 casualty in your favor. And now there's an important difference between +1 and -1 results. On average, it will take a force 7 times larger than the plate-armored one, in order to wipe it out completely.

So a force of 500 Spanish swordsmen won't go down unless it's attacked by 3500 Tlascallans -- which the morale system won't allow to happen all at once! On the other hand, the Spanish can realistically kill a number of unarmored enemy warriors equal to themselves. This is probably enough to clear out at least two "morale boxes" from the previous example. So if the morale roll is around 7, the highest boxes will be killed, and the lowest boxes will run away. This result looks like it's perfectly reasonable, a sign that this approach is on the right track.

Next project: Making a mock-up battle board and doing a fully detailed example that includes box placement, ranged and artillery barrages, a morale check, and the application of casualty results.

Friday, July 5, 2013

Fantastic Frontiers: Combat Example

Previously on this channel, I described the idea of having the random aspect of combat be something that determines which portions of an army actually contribute, and which just stand around watching. This sounds a little silly to someone with only a Hollywood-level exposure to warfare, where battles seem to consist of everyone firing at everyone else in a frantic melee. But in a more realistic environment, the primary challenge of a commander is getting troops to move up to the front lines and actually engage the enemy. A detailed study of the psychology of warfare suggests that convincing human beings to function as cold-blooded killers isn't as easy to accomplish as it might seem. (The majority of combat casualties are inflicted by a handful of psychopaths who finally find themselves in an environment where there's no stigma against their psychopathology!) In fact, humans are mostly like other social mammals, in the sense that we'd really rather defeat an opponent by posturing and creating the appearance of a threat, rather than actually having to deliver on that threat's promise.

In a game system, it's not sensible to model the psychology of the 3 to 20% of individual soldiers who are going to inflict 50% of the casualties. Instead, it's more sensible to create aggregate representations of the behavior of a unit that reflect the probability that the overall psychology of that unit will be swayed by that minority. That is, you just tweak the probabilities of winning the battle (a binary outcome) up or down a sliding scale that gets adjusted by various modifiers to reflect how easy it is to get your bloodlusted barbarians to sweep along the rest of your unit into the fray.

This isn't as much a kludge as you might think. The strangely formal styles of formation warfare that dominated Europe seem odd to us in the modern world, since we have weapons that kill at a distance, and thereby minimize the psychological distress of having to hack apart an enemy with a hunk of sharpened metal. But in the era of broadswords and longbows, the idea of conditioning soldiers to march in an orderly formation was a sort of essential trick to get them to stand in places where they had no choice but to participate in a fight. If the formation broke apart or lost cohesion, its bewildered soldiers all at once stopped fighting and just tried to stay alive.

Let's walk through an example of a large-scale battle. In the second engagement between the conquistadors and the Tlascallans, a relatively tiny force of 400 Spaniards was able to force a vastly larger force of tribal warriors. Bernal Diaz doesn't provide an estimate, but it hardly matters, since even if the entire army of 100,000 Tlascallan warriors arrived on the battlefield, there would be no way for them to simultaneously make contact with a tight formation of Spanish rodeleros. Instead, the Tlascallans would essentially be forced to line up and come at the Spaniard in waves, in a classic display of mook chivalry. If they could break apart the Spanish formation and come at it from multiple sides, then suddenly they could press their numerical advantage and put four of their warriors on each isolated Spaniard; indeed, a cavalier named Pedro de Moron had fallen to them in precisely this way in a battle a few days earlier. So the real question that a dice roll needs to resolve is what happens first: the shattering of the Spanish line, or the retreat of the Tlascallans.

Visualize a set of boxes labeled form 1 to 12, which represent the cohesion and morale of any given unit. The Spanish are probably going to get to place all of their 13 muskeeters, 13 crossbowmen, and 13 horsemen, and some fraction of their infantry (say, the first 100) in a very high box. Let's put them in the [10] box, which means that there's only a 3 in 36 chance that they break. The remainder of the infantry will go in lower boxes, representing the chance that less courageous, diseased, or wounded soldiers might be more likely to break off. We'll put 200 infantry in the [10] box, another 200 infantry in the [9] box, and another 100 in the [8] box. Here we're assuming a total infantry force of around 500, based on Diaz' records.

The Tlascallans will be broken down in the same way. Their placement reflects morale more than discipline, although their lack of military training will probably force them to start in a much lower box and have a reduced chance of passing a participation check. They only have militia-quality infantry (no horses or muskets!) so we'll start them with 200 infantry in the 8 box, then another 200 in the 7 box, and so forth down the row. These reflect the waves of combatants arriving one wave at a time. Note that the guys in later waves are going to have very poor morale, since if they battle isn't over by the time they hit the fray, they've already seen several hundred of their kinsmen mowed down by steel and gunpowder. After the first 500 or so of them have fallen, the remaining legions in reserve just aren't relevant to the battle, since they're likely to lose their enthusiasm for battle under some internal pretext and just head home (as indeed, they historically did due to infighting between their commanders).

To represent the effect of long-range guns (muskets, crossbows, and artillery), we'll let the Spaniards take a few potshots at the front wave (the highest box). They'll knock out some of the 200 enemies in that box, which is particularly useful, since that's the box most likely to be included. The Tlascallans might have a few spear-throwers and slingers, but those projectiles are likely to bounce off of breastplates made from good Toledo steel.

Now we roll a 2d6 check for each side. For the Spanish, the represents their efficiency in staying in formation. For the Tlascallans, this represents the number of waves that will be available strike and fall before they collectively lose heart and call off the assault. Statistically speaking, it's pretty likely that the majority of Spanish will hold the line, while only a few waves of Tlascallans will participate. Let's assume average rolls for each side of 7. Then the Spanish will get all of their infantry fighting at full discipline, and the Tlascallans only convince 400 of their warriors to run screaming at the Spanish line, some of whom have already fallen to matchlocks and falconet grapeshot. So effectively, this fight reduces to the Spanish just having to endure the casualties from fewer than 400 opponents who will fall quickly to their superior steel blades. Much less daunting than having to eliminate all 100,000 in a single afternoon!

Of course, things could have gone much worse here for Cortes. If his line had partially broken (say, a roll of 10 for Spain, that costs him 300 of those infantry), then most of those guys are probably going to be dead weight, and the other half of his force will need to work twice as hard to bring down the Tlascallans. And if the Tlascallans themselves suffer from less internal dissent (say they roll a 4!), then there will be more like 1000 enemy warriors to defeat. This pretty quickly is going to turn into a nightmare outcome for the outnumbered conquistadors. We'll be generous, though, and assume that the troops that fall out of formation somehow manage to flee and regroup a few miles away. (More realistically, they'd probably end up being rounded up to be sacrificed at the summit of some step-pyramid...) That gives the Spanish a chance to continue their exploration of the countryside, albeit in a weakened state, so that the entire game doesn't end on a single roll.

This kind of combat is highly "swingy". In fact, for a less frustrating game, it might be necessary to artificially reduce the randomness in some way. Any easy approach is to provide some check modifiers for quality commanders and other situational effects, to give a nearly 100% chance that at least some portion of the Spanish troops will pass the check. (Maybe Cortes adds a +2 modifier to the top box for his personal charisma and persuasive charm -- "The more Moors, the more gold!" -- or something like that.)

What if one side doesn't get to include any of its boxes? Then the entire opposing side (even the troops that didn't pass their own check) gets to simply pick a single opposing box to crush, to represent the ensuing battlefield rout. (The troops in the other boxes will scatter to the winds and escape with life, if not dignity.)

What if neither side includes any boxes? Then both sides stare at one another as they reload and the commanders rally their troops, and the whole procedure repeats from the top with new ranged and artillery barrages. Probably bad news for the Tlascallans, who can only toss stone javelins!

I still haven't discussed the question of how to calculate casualties. Most of the Tlascallans will end up mortally wounded by superior weapons, while most of the breastplated Spanish will take only superficial injuries to their extremities (and maybe suffer a few casualties to infection over the next week). Calculating the casualties will be something that depends on armor quality and on the morale check roll -- the one consolation of rolling badly on a morale check is that at least the battle ends in a hasty retreat before you've suffered many losses. While both sides care about losses during the initial barrage stages that cut down the high box formations, the final losses after the morale check can really be ignored for the Tlascallans, who essentially have infinite reserves.

Thursday, July 4, 2013

Fantastic Frontiers: Morale and Seaboxes

For a game that focuses on high-level decisions (resource management), instead of tactical decisions (who attacks what), it's important to have a fast combat system. Wargames have fast combat, usually based off a single dice roll, and so they can include lots of resource management. Computer games can have pretty complicated combinations of dice rolling, but as long as they hide it in the CPU, it's all instantaneous. Early RPGs also used pretty fast and abstract systems (before the days of miniatures and grids), at least compared to today, and could easily fit a dozen battles into a single session. Obviously this is the kind of effect we're going for, in a hex crawl board game.

But it's also important to emulate the feel of what would happen with a detailed miniature or man-to-man system. A group of knights in plate mail should feel different (and actually play different) than a group of footmen, or archers, or elven pegasus-riders. The trick is to get the feel of a more complicated system without the time expense. That requires some kind of "fast combat" system that's more akin to the single dice roll of a wargame, as opposed to the "moving dozens of little figures" feel of a miniatures system.

Fast, of course, is a relative concept. I don't mind if battles take 10 minutes or so. But it's important that they scale sensibly. That is, if it takes 5 minutes to fight a battle with twenty combatants on each side, I don't want it to take 50 minutes for a battle with 200 combatants on each side. I'd say that an upper bound of around 10 minutes for a complicated battle is my limit. Scaling needs to be much less than linear. This is the opposite of most tactical battle systems, which scale worse than linearly (doubling your armies more than doubles the time it takes).

The simplest option would be to just given each unit a combat factor, and then calculate odds and roll the result off an odds table. That would probably take only a couple minutes. But it's not very interesting, and it doesn't capture the different feel of having different types of armies. The strategy of the game reduces to "get the most factors on the board for the least money".

I'm shooting for a game that defaults to the age of discovery (say, 1450 to 1650), a time when heavy breastplate armor overlapped with primitive cannons. That's not quite medieval any more, but not quite Napoleonic either. There are a few concepts I think need to be included in any good simulation of early modern warfare:
  • Matchlocks and crossbows
  • Field cannons
  • Melee weapons and armor
  • A discipline/morale system
The last of the four elements is the most important one to me, so it's where I start. Discipline and morale are the reason that 500 conquistadors can hold their ground against 10,000 tribal warriors. Any simple combat-factor system can't capture that dynamic. The really important question isn't so much how large the sides are, but who actually shows up at the point of contact between the opposing lines. That's a question of concentration of force.

To imagine how this might work, I'll talk a little about sea boxes in World in Flames. Sea boxes are an abstraction in naval combat that represents how likely it is that a given ship will arrive in a particular battle (that is, "find" the battle). Ships with more mobility get to occupy a higher box, and a search roll determines whether they're included. This is a roll-low system, and everything under the sea box value arrives to fight.

The "4-box" means a 4-in-10 chance of being included in the battle.



Once the battle begins, the casualties are mostly deterministic, with some adjustments for which side is more surprised. But mostly, it's a matter of figuring out what ships arrive at the point of contact and participate. That's exactly the idea I want!

Imagine that instead of having box numbers representing search capability, for ships wandering around on an empty ocean, we have boxes that represent morale and military discipline. A high "box" represents lots of morale, and the unit will bravely assault in the front lines. A low "box" indicates that the unit is cowering in the rear. With a 2d6 roll-low morale check, that would amount to giving each unit a morale "box" value between 1 (never participates) and 12 (always participates), with a bell curve of possibilities. This morale value could reflect both intrinsic properties (like training) and also situational ones (like weather or supply level).

This post is running a bit long, so next time I'll give an example of how this concept might work in practice. This approach to combat will be a little more complicated than WiF's system, since it will need to include not just melee engagements, but also the opening volleys of guns and artillery that can themselves adjust morale modifiers (nothing saps morale like seeing a row of musket barrels aimed at you!)