Shields up! The enemy is approaching.

Mass Combat

One of the greatest challenges of roleplaying games is the very thing they evolved out of: Mass Combat.

Freeform Mass Combat

My most recent brush with mass combat happened in a game of Lamentations of the Flame Princess, where the PCs got wind of a planned raid on a monastery, and decided to prevent it. The attackers were supposed to be 117, all told. The targets were 74 monks and 2 elves.
However, in the course of the adventure the PCs already took out 44 of the would-be attackers and had a head start. They recruited a group of armed soldiers and some farmers from a nearby village, and they convinced a good number of monks to at least threaten the attackers. So the final tally was 73 attackers versus 122 defenders lying in wait.

How to resolve this situation?
The players already decided on their positions and distributed other folk to various places in the area.
As quasi-ambushers, the PCs got the first shots, then we did group initiative. Individual initiative would be madness with 200 combatants. Every PC could roll attacks and damage for all the NPCs under their respective command. That would be 12 in one case, 14 in another, 8 in another, depending on troop positions.

Switching from unit to unit depending on tactical situation and reloading times — this was made easy by the fact that the attackers had only two bridges they needed to cross, so the bridges were the hot spots, and other areas stayed calm. Terrain helped to keep this battle organised.

The situation warranted a short combat: After only four rounds, the attackers had suffered relevant losses of 20, plus wounded, and had only managed to kill 3 and wound 6 of the defending force. It looked as if they would lose more than two thirds of their number to even cross the river, and then the battle for the buildings beyond would only just begin. That kind of results in the first skirmish makes the job of a commander easy. Terrain allowed for a swift and comparatively easy retreat, so the attackers turned tail and ran into the woodland.

In other circumstances, like, an open field battle, the battle would have to be seen through for longer, taking, potentially, hours. Even so, it was slow, and frustrating for players itching to go while the focus was on the other theater. More people, more waiting.

So: What rules to use for a more open, more abstract battle, or a battle with combatant numbers running into the thousands?

The answers out there are various, and I do not know them all. I do not know the mass combat rules of “Legends of the Five Rings”, which I heard are good. Neither do I know “Way of the Earth” which is said to lump units together like individuals – a bit like S&W or FATE do it, which will be discussed later. But let us start with …

GURPS Mass Combat

GURPS has a quite coherent mass combat system which was first introduced in the sourcebook “GURPS Japan”, and later published as its own thing, because mass combat comes up in many settings. The GURPS system is, of course, highly abstract and works a lot with percentages, starting from a unit rating and building on it, depending on equipment and special skills or powers, as well as rating units by experience and commander skill, until it suddenly drops the ball and claims that of all the casualties, half are dead and half are wounded. A very rule-of-thumb decision after ten pages of detailed calculations. That doesn’t change that the GURPS approach represents one of the most serious efforts to solve the mass combat problem that I am aware of.

BECMI Mass Combat

The BECMI DnD system follows a comparable path. Like GURPS, it works with a unit rating and special equipment and power modifiers, also with experience and commander skill. There are differences, though, especially when it comes to casualties, where BECMI works with a table based on the amount by which a battle-dice-roll was won or lost. Like GURPS, it demands some arithmetical skills. Like GURPS, it also learns from Conflict Simulation Games in the sense that a power imbalance in the force strength and terrain features have a serious impact.

“I have the high ground!”

popular sci-fantasy character

Swords & Wizardry Mass Combat

Swords & Wizardry, a clever ODnD clone, lumps groups of 5 or 10 soldiers, or, potentially, 100 soldiers in the guise of 10, into 1, treating it basically like a single character with oddly bloated hit points and much slower movements. So 10 versus 5 soldiers would fight just like 2 versus 1, with the same kind of weaponry, and slowly bleed out, striking off single component soldiers whenever their HP-number is met, while moving in 5-minute-rounds, and taking one full round to re-orient itself towards the flank

This has some obvious advantages:
For one, it is easy, even for algebra-failures.
For another, it goes abstract very, very fast. 20 men trying to cross a river and 10 defending it, is easily re-created. The same is true for three groups of 7 each attacking and two groups, one of 10 and one of 14, defending.

One of the problems is the comparative loss in damage differences. 10 soldiers do more damage than 2 in one round. But not in S&W. It balances out because the damage done is ALWAYS low, and the 2 soldiers die faster than the 10, but it creates a disconnect to the narrative that can become a problem, at least sometimes. The second issue is that it is quite hard to incorporate individual player characters in this time-freeze-stylized mega-human-combat. But that is a common problem. Usually, the mass combat rules take a step back to consider the whole playing field, and lose the single PC in the fog of war.

That is just nitpicking, of course. In my opinion, Swords & Wizardry managed to get as close to a workable system as conceivably possible. This solution is way better than RISK, and RISK has defenders and fans around the whole globe. So here’s respect to Swords & Wizardry for an excellent mass combat system, as far as they go.

FATE Mass Combat

FATE is a Fudge-based system with a very strong narrative focus that builds characters out of descriptions. It has a special rule – the so-called “Bronze Rule” or FATE Fractal, which states that “everything is a character”. That means, that you can build any car, house, storm, or, for the matter at hand, military unit or even whole army, with the same building blocks you would use to make a single character.

The trouble is with FATE damage, which is expressed in narrative terms that do not well mesh with bloody war. FATE is heroic. People break a leg or get blinded, but they fight on. The same is, rules-wise, true for platoons. FATE is not really suited to handling the loss of half the combatants in a unit.

Into the Odd / Electric Bastionland

Into the Odd introduces “Detachments”, groups of a good number of people that have HP and STR like a single human, but are invulnerable (in ItO) or relatively resistant (in EB) to attacks from single foes. It is easy and quick, with the one problem: It does not work for mass combat. The ItO Detachment is fine for a confrontation between a group of PCs with 20 hussars, but playtest shows that it does not well reproduce the 20 hussars against 15 sailors.

Adventurer, Conqueror, King

I have never played the much loved and much hated system ACKS, which is based on DnD B/X, but deviates from it in numerous aspects and has its own “Domain Level” rules set. It lumps individual soldiers into groups or units, like 120 infantrymen, or 60 horsemen, and then goes on to use them like single characters with certain weapon and armor stats. It gives the units a Battle Rating — just like GURPS and BECMI — considers magical effects, makes divisions, and starts hacking. Hackin in 6-second-rounds, so there is not slower movement for large bodies of men. Casualties are then determined like in GURPS: 50% dead, 50% wounded.

It is rather detailed and it has one great advantage over other mass combat system: It actually took the time to think hard about the role of individual player characters in the midst of a battle, and about the impact these player characters can have. Which is considerable once they hold command positions and shape the fate of thousands, but quite low as long as they are one of the common foot. Which makes sense.


Someone mentioned Traveller to me, but as I looked up the rules of mass combat — they have that — I found it complex and far removed from immersive roleplaying gameplay; so I discarded it soon. If someone here knows a reason why Traveller mass combat rocks, speak ye, or be silent furthermore.

Stars without Number

Speaking of Science Fiction, I got told that Stars Wthout Number had a great system for battles .. and it turns out that yes, it has, but that no, that it is clearly a ship combat system. A star-ship combat system even. A good one, mind you, but star-ship combat is a very different beast from a cavalry charge. Its closest approximation in our world is an u-boat-battle.
So Stars Without Number is definitely cool and deserves to be looked at, but it will not provide a good mass combat system for foot soldiers.

Forbidden Lands

Forbidden Lands does. It is a small-scale nordic RPG. I do not know a lot about it, except that it was printed in Latvia and the teams’ names have a swedish and mayhap baltic ring. The system is a dice pool system á la White Wolf, but with six-siders; and not only six-siders, but unique ones with skulls and crossed swords etc.

This sounds like it makes it difficult to integrate into another game, but not so, bear with me. The dice pool mechanic is quite well thought out, especially with regards to mass combat. A force of, say, 10 or 20 fighters gets one die to roll, and can add more dice through advantages like cover, superior arms, magic, etc. Attacking a fortfied place halves a fighter’s worth (or defending one doubles it, depending on how you want to look at it).

Then both sides roll, and every six that comes up decimates the opposing force.
This part is what makes the system quite versatile. It does not roll for victory, it rolls for damage. How that affects the outcome is open to GM interpretation. This approach also makes it pretty easy to integrate the actions of individuals into the fray that happens in normal combat rounds.

Throw Me A 6

Closely related with the Forbidden Lands approach, maybe even the progenitor, is a dedicated mass combat system by the name of Throw Me A 6. The name is also the program: Units square up and fight. At a basic, troops roll 2 6-sided-dice. Troops are light or heavy, cavalry or infantry, and raw or veteran, and their relative superiority gives them more dice to roll; disadvantages give them fewer; but a minimum of 1 die remains. They move and shoot, then follow melee fights. Each 6 is a hit. Units have usually a strength of 4, and are routed when they lose 3 of them. Once one side loses two thirds of their total number, they have lost.

The design philosophy of Throw Me A 6 is simplicity. As such, it is quite a good choice.


RPGs evolved out of mass combat, as I said earlier. They rose from the desire to concentrate on individual soldiers, not faceless units. And so, the older DnD editions did not need mass combat systems. They came from Chainmail, and references to its rules, which is nothing less than a Fantasy Conflict Simulation using miniature figures to represent units in a combat. It has important rules that other systems overlook, like pass-through fire on the move, or firing in an arc over friendly units. Stationary longbow units can shoot twice in a round, once after the first half of movement, once at the end of the movement phase, if they are not engaged by melee units at that point.

The system has a bit more complexity thanks to combat results tables, and some serious gaps, that were likely houseruled back in the 1970ies. But it is, as the “father” of DnD proper, closely aligned to the spirit of RPGs and full of narrative potential. Specific outcomes and the fate of routed units can be managed by DM fiat.

Do we have an answer?

Maybe. None of these systems is perfect. For me, Swords & Wizardry is the winner, but you might think different. A close contender is ACKS Domain play, which is obviously very carefully designed and deserving of respect. It is almost a CoSim in its own right.

In all honesty, dedicated Conflict Simulations are best to handle military engagements on larger scale, as they were designed to do that very thing, but that would mean stopping the RPG game to start an extra game in the game … not to speak of the issue that single characters cannot be represented in a regular CoSim. If it is a sudden military engagement that is in the way of the adventure proper and where a long tallying of units would just cost valuable game time and feels unproductive, Throw Me A 6 and freeform are more attractive.

The OTHER freeform (not mine)

To remember: My free-form system, described up top, was to give every PC a number of men and he can order them around and roll as many attacks as there are troopers in meaningful tactical positions; that often meant 15 or 20 attacks. This was slow, but with a good focus on the individual character and his or her achievements and risk.

Variant 1

The OTHER freeform version (inventor: unknown to me) comes in two variants, as I have seen it. Variant 1 is rolling with d20s. The stronger unit gets 2 d20, or the stronger one with magical assistance and prepared territory gets 4d20, against the haphazard attacker with 1 d20. Higher roll = Victory.

Variant 2

Variant 2 works with different dice steps. The haphazard attacker rolls, say, a d8. The stronger unit (d10) with magic (d12) and territory (d20) goes up several steps. This is not arithmetically perfect, as the difference from d4 to d12 is always 2, but then there is the gap to the d20, which only DCC funky dice can bridge. Again: d8 vs d20, higher roll wins.

Both variants share that after the roll it falls to the GM to clad the bare numbers in a narration that makes sense. The bigger, stronger, buffed, better prepared army may lose, or win by only a small margin. That must be explained somehow, due to some glitch, as they frequently happen in real-life mass battles too: Fortune favors who she will, as history proves.


(Playtest: Swords & Wizardry Mass Combat versus Roll Me A 6)


Image: Siggy Nowak on Pixabay

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