Book of War vs. Chainmail: Goblin Battle

Mass Battle Test: Employing the Delta’s “Book of War” Rules by Daniel R. Collins, which were designed to arrive at statistically similar outcomes as the Chainmail Rules would, but with much lesser complexity.

We shall run one and the same scenario twice, once with Book of War, and once with Chainmail.

The setup

A band of 60 goblin raiders, 20 archers and 40 spear-carriers of the Broken Tooth , race down a wood trail to attack the cave warrens of a rival tribe, the Long Toes. However, the Long Toes are ready for them: They race right at them from the opposite side, 80 spear-carriers strong, and they bring a secret weapon: A gang of ogres who are lumbering behind them at an unstoppable pace.

The Long Toes are quite confident about this encounter, as they come prepared. A world of pain awaits the Broken Tooth goblins.

Terrain: Wood. That means, off-road movement is halfed.

Meeting the foe

The two forces meet in full swing somewhere on the road. Neither side has actively chosen this particular spot. Initiative with 2d6 each: 4 for the Broken Tooth, left. 6 for the Long Toes, right. The Long Toes have first pick. Each player has three phases to handle: 1) movement, 2) attacks, 3) morale.

Each figure represents 10 goblins. Round-ish are spears, diamonds are archers. The square is the ogre reinforcement group.

Goblin movement is 9″, so at the moment of impact they are already within striking distance. The ogres are a bit behind but will reach the melee in a moment.

We start with movement. And the lead 10 goblins are bust.

But only barely: Of four figures attacking, only one hits and does the necessary damage to eliminate the vanguard. Lucky for the Long Toes to score with such a dismal performance.

We go right to morale: The 40 Tooth-spearmen have lost 25%.

Morale roll is 2d6+1(HD)+3/1, and that must be 10 or more. 2d6 is 8, the Broken Tooth Goblins are angry and stay. A big difference compared to Chainmail: Morale is highly dependent on HD, while in Chainmail it depends on troop type and armor.

But back to the moment.

Movement: The attackers pile up against their numerically superior foe. They need a slight reformation; a half-move is enough for that, and they don’t need so much distance.
However, the archers cannot safely shoot. Shooting into melee is not in the cards in mass combat. But the bow-goblins spy the lumbering ogres within their range. Not their half range yet! So -1 – stand and let fly. Rate of Fire is 2.

Two hits against the ogre Armor Hit value of 5. But the ogres have 4 HD — they are at half strength after a volley of arrows pierces them and several fall under the sharp barbs.

Attacks mean the roll of 1 six-sider per figure in melee on its turn. The spearmen slay 10 foes, and we replace them from the back ranks.

Ogre morale: 2d6+4+0,5. 6 + 4 + 0 = 10 exactly. The ogres are deeply unhappy, but stay.

Spearmen morale: 2d6+1+7. 18. They are highly motivated.

Round 2:

Init 7 vs. Init 9. The Long Toes win, and that is important, because the ogres narrowly manage to engage the archers in melee.

The spearmen eliminate 2 out of 3 figures. The ogres hit and crush half of the archers.

Now the spearmen lost 2/3.

2d6+1+1/2. The 2d6 come out snake eyes. 3! The last 10 goblins throw down and run away!

The archers: 6+1+0 = 7 They also run!

After 40 out of 60 Broken Tooth goblins are struck down, the last 20 turn tail and move a full 90 yards away.

Round 3:

Initiative decides:

8 for the fleeing Broken Tooth, only 5 for the pursuing Long Toes.

The Broken Tooth goblins flee faster than the Long Toes can chase them. So the 20 survivors escape.

The End!

Victory for the Long Toe goblins, with the loss of only 10 spearmen and 5 ogres, compared to 40 enemies.

As promised, Book of War is fast and easy, and the result is believable.

Just to be sure,

let’s repeat that same battle with Chainmail.

The same setup, the Broken Tooth goblins come running, they meet the Long Toe goblins, the archers stay still, the spear units clash.

We need base contact for an attack, but two rows of spears can attack. So again we get four figures to attack, they are just not the same four.

The next difference is that we need more dice. A lot more dice, because we are rolling per man, not per figure. Which is, in our case, 10 dice for 1 figure. Which in turn means that the statistical reliability of outcomes rises with higher troop numbers, since more dice tend towards an average. Small units will have an easier time diverging between the two systems because two dice rolling wrong in Book of War have a great impact, while two dice in Chainmail are not significant.

Anyways! Our spearmen roll.

And again, the vanguard gets slaughtered with a slight overkill, but since we have no base contact, the goblins farther back are safe.

We also have pass-through fire as the ogres move at the archers. Goblins attack as heavy foot. Ogres count as six heavy foot. twice ten archers shooting at heavy foot; they do 3 hits each. We can count that as one ogre going down. 9 remain to storm on.

But in Chainmail we play alternating rounds, so we know that now is the archers turn and they can shoot twice.

The archers keep going and take down two more ogres with 3,3,3 and 3 hits. The ogres are down to 7.

Meanwhile, the spearmen attack their opposite numbers: Sixes kill. We have 5 on top, 4 in the middle and zero below. That makes 9 Long Toes down. A pretty similar result to Book of War on both counts, even though the we have two more individual ogres alive and one more individual goblin.


The side with fewer casualties (the Long Toes) determines the positive difference between their and the enemy’s losses. (1)
This is multiplied by the result of a die roll (3).

The side with the greater number (also the Long Toes) determines unit strength difference (41) and multiplies by moral rating (5). The difference is a whopping 208, and calls for an immediate and complete surrender of the smaller unit.

What happens to goblins surrendering to another tribe? Probably nothing fun. But the combat is over for them, much sooner than in Book of War, and with fewer in-combat-casualties. But what if they would not surrender? In that case … [dice rolls, dice rolls] … they would get pretty much slaughtered and only a handful would be able to turn and run. Almost exactly the outcome of Book of War, only that there the number of survivors is simplified as one figure = 10 goblins, instead of, as per Chainmail in this test run, 6 goblins.

Ogres vs. Archers

We turn to ogres versus archers and have the ogres close the remaining distance before the archers can loose another volley.

The 7 remaining ogres attack as 6 heavy foot each, so 42 heavy foot against 20 archers.

The ogres kill 17 of the archers.

The remaining 3 can flee with the surviving 6 spearmen.

In Book of War, 10 archers and 10 spearmen ran away.

In Book of War, our ogres were at half strength in the end, in Chainmail seven out of ten were left.

Bottom Line

As promised by the rules booklet, Book of War delivers very similar outcomes with a lot less effort (rolling 4 six-sided dice instead of 42 for example, and rolling 2d6 for morale instead of calculating differences in troop strength and multiplying them with a morale score per type of unit).

The victories resemble each other very closely. The difference is: In Chainmail we zoom in more and determine the fate of individual men (or goblins), (as we did in this battle) while in Book of War we determine the fate of units.

Book of War is faster and easier. It is the better choice to determine the outcome of a battle within the context of a roleplaying game, when we may want to determine the fate of specific individuals by the RPG rules in single combat, and our goal with the mass battle is to find out how it goes.

Chainmail is more math-heavy and is best suited to set the time aside and really focus on the battle; if we have a full bag of d6es and really want to know if we get 20 survivors or 13.


Valuable Feedback from DeltasDnD:

  1. Book of War actually tries to simulate Dungeons & Dragons combat at scale, not Chainmail per se; although there is a strong overlap since the two are intervowen, and especially with OD&D referencing back to Chainmail for certain situations, most importantly mass combat.
  2. Book of War Initiative is rolled only once, then the sides alternate.
  3. Morale rolls in the revised version of Book of War will have a target number of 9, not 10 like in the previous edition.
  4. Quite interesting: Delta points out that in 2005 Gary Gygax was asked to clarify, precisely because of his inconsistent use of “figure” and “man” in the Chainmail rules [“1 figure representing 20 men”]. He then stated that when he says to roll “1 die per man” he actually means “1 die per figure”. So I was breaking out the big piles of dice in error and could have done with 4 or 5 all over.
    However, I don’t regret it: it was pretty evocative to see the individual goblins fight for their lives represented by these dice… and it was manageable with these platoon-sized groups. But I must admit it would become rather exhausting in a battle of 6000 cavalry attacking 10,000 heavy foot. After 10,000 dice rolls in a row even the most enthusiastic dice-aficionado is going to need a break.
    And: It means that the outcomes of these two battle-versions could well have been absolutely identical.

This and much more (including links to his OED, BoW and other rules), and to his biweekly Book of War playtests (youtube link) can be found on Delta’s own blog.

Another thought: I am happy to see that this playtest inspires more gamers to try similar experiments! I hope to see the outcomes.

More Mass Combat posts:

2 thoughts on “Book of War vs. Chainmail: Goblin Battle

  1. Thank you, Michael. That’s already addressed in Delta’s feedback, but I guess it won’t hurt to state it again. Gary Gygax used the terms “man” and “figure” interchangeably, but cleared this up in an interview in 2005.


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s