Monday, October 24, 2011

Book of War: Pikes

Pikes are particularly nebulous in the D&D man-to-man rules. In OD&D (Sup-I) they are simply listed as being flat-out inappropriate for dungeon work; the effect of their reach has no rule specified until the AD&D DMG; and at no point are any rules given for the effect of mass pikes (except, perhaps, for Chainmail mass-combat, where they simply cannot be attacked by any non-pikes). We discussed that here as part of last spring's "Basic D&D" posts -- below you'll see the outstanding questions I asked at that time (with apparent commentator consensus in bold):


  1. How many ranks of pikemen can strike offensively, say 3? Yes.
  2. How many ranks of pikemen can strike defensively, say 3? Yes.
  3. How many ranks of pikemen can "set" for double damage, say 3? Yes.
  4. Do we allow an attack by pikes to "interrupt" the movement action of an opponent (even by a pikeman not individually the target of the attacker)? Yes.
  5. Can pike "interrupt attack" any number of attackers during a turn (versus some limited number, say, 1 as in 3E)? No.
  6. When used against charging cavalry, can the pikemen all opt to strike against the riders? (Or is it 50/50 riders/horses? Or more likely against the horses?) No (average response 75% to hit rider).
  7. Do pikemen get a "formation bonus" to hit defensively due to closely-packed spikes? No.
  8. Does a strike by a pike vs. an attacker end the attacker's move? Yes.
  9. Does a kill by a pike block other attackers moving through the same zone (either by piling up bodies or "skewering" upright)? No.
  10. Do we need to establish special rules to simulate the organization/formation requirements of properly using pike? Mixed.
  11. Do we permit heterogeneous formations (pike & halberd, pike & crossbow, pike & shot, etc.)? Yes.
  12. If a man drops the pike to use sidearm sword, can he later pick the pike back up? Yes.
  13. Do pikes cancel the cavalry rider AC bonus? Yes.


So clearly we all agree that about 3 ranks of pikes can strike (whether on attack or defense), that all of those can make an interrupting attack against enemy movement (obvious, but even that not explicated in D&D until 3E), and that pikes cancel the rider AC bonus from height (which syncs up with what we said for cavalry, here). Those are Questions #1, 2, 4, and 13 above, which are included in the Book of War rules. Ironically, if you dig into the details of the RPGBattle simulator here, you'll see that almost everything else got baked in exactly opposite to those responses. Ha! Let's see if I can explain why:


Problems With Pikes

The main problem (as discussed last spring) is that core D&D hit chances are really quite low, too low to provide much of a defensive benefit, in the absence of some other to-hit bonus from a massed pike wall (and absent it is from any classic D&D rules). Look at Questions #6-7 above; these are sticking pretty close to published D&D, with no formation bonus like I'm suggesting, and a significant chance to hit the horse instead of rider (note that that decision itself almost winds up negating/replacing the "pikes cancel AC bonus" decision in Question #13).

Consider a line of heavy cavalry charging into our massed pike wall, 3 ranks deep (all normal men). To-hit against AC2 is 17+ (4 pips). If there's a 25% chance to hit the horse (Question #7), then this is reduced to 3 pips in 20, i.e., probability 3/20 = 0.15. Hence the following is the chance for the rider to get through the thicket totally unscathed:

(1-0.15)^3 = 0.85^3 = 0.61 = 61%

So unfortunately, that doesn't serve the historical strategic purpose of pikes definitively holding off a cavalry charge from heavy cavalry (and in many sources, being almost totally invulnerable to such attacks; see also the Chainmail mass rules comment). Almost 2/3 of heavy cavalrymen can run through a pike thicket without a scratch! When I simulate this rule in RPGCombat, it turns out that the pikes actually suffer more casualties than the cavalry when they get charged. So I think we have to say that the existing (very sketchy) D&D man-to-man rules for pikes are simply insufficient for this project.

Of course, AD&D establishes the "set pikes do double damage to charging attackers" rule, but if you think about it, that rule does surprisingly little good for our purpose. The problem is really that the to-hit rate is too low to connect with most of the men charging through the pike wall. You could increase that damage multiplier to ×100 and still the majority of heavy cavalry will move through the pikes without taking any hits. And this non-relevancy is compounded by the fact that against normal men, a single hit usually kills them anyway, whether damage is single or double or anything else. (Note: The response to Question #3 -- all ranks can set against a charge -- seems counter to the rule on DMG p. 66, where the pike butt must be set on hard ground surface; to me that seems doable only by the front rank. But as we see here, the difference is of mostly academic interest anyway.)

Also, regarding Question #8 (yes, a defensive pike hit stops the enemy move forward), this is something that seems pretty reasonable if we picture the enemy as only a normal man. But we also need to deal with things like a charging horse, or in our fantasy game, things like lumbering ogres, giants, and dragons (far more likely to have inertia to snap the pike and keep coming?). So I'm very hesitant to establish that as a general rule (and it's not in D&D, and it's the same problem as Chainmail flatly disallowing anything to attack pikes -- okay for normal men, but doesn't scale to fantasy monsters).

And here's another counter-intuitive result that comes out of the simulator: the more you dial up the pike damage multiplier, the more casualties the pikes themselves take. This is because to whatever degree an attacker might take a hit and stop coming, yet survive and block the attackers behind him -- now turns into a downed attacker, and an opening for other attackers to keep charging (no further pike interrupt per Question #5; and no blockage from dead bodies per Question #9). That's a result that really boggled me when I first saw it.

One more thing: 3E gave a cover penalty to any reach weapons wielded from the back rows (+4 to AC; PHB p. 132), but that would immensely exacerbate these problems. (Like, for us, men in heavy armor would be totally un-hittable by anyone in the back ranks). Therefore that rule was never on the table, either.


Solutions in Book of War

So this was one of the few places in BOW where I was willing to switch significantly away from by-the-book D&D man-to-man rules (in that quite defensibly, it avoided mass pike issues in the first place) and come up with something that made our game play out reasonably well as a priority (which was the core of the crisis that I had last fall). The primary thing I did is to institute a "formation bonus" (Question #7), which is to say, a hefty "you can't dodge this" modifier when you get into a restricted space with a bunch of pike-shafts hemming you in on all sides, which I ended up setting at +4 bonus value for the mass pikes (or, +1 in BOW d6 space). This made it at least possible for pikes to hold off an charging enemy, even if it's still not a sure thing (it's possible in BOW for heavy cavalry to attack pikes, and with some semi-lucky die rolls, still manage to get through). Again, the to-hit level is really more critical than any damage multiplier.

Here's another thing I had to consider: We now have a whole litany of if-then situations we could theoretically apply for the pike attacks rule. Such as the following:
  1. One rank, or many ranks of pikes? (If a BOW player sets up one figure-rank of pikes, that's only 2-man ranks, so they don't get the full force of the pike benefit; two or more figure-ranks, however, is more than the 3 man-ranks we agree can all strike.)
  2. Infantry, or cavalry target? (Per Question #13 here, we all agree that the cavalry AC/target modifier needs to be washed out when the target is attacking cavalry.)
  3. Defensive, or attacking use of pikes? (The pikes could theoretically set for double damage in the first case but not the last; and also there's a difference in commitment to the opponent willing to run themselves through the pikes.)
  4. Rough, versus open terrain? (In our mass combat, we also want to reflect the decreased utility of pikes in irregular, rugged terrain.)
So if we directly handled all of that in BOW, there would be at least 4 if-then clauses to the pikes rule that you'd have to parse every time they were used -- equivalent to a 4-dimensional matrix with 2^4 = 16 different individual use-cases. (And if Question #10 had gone "yes", then that would have added a "5th dimension", which is then not even a game from TSR.) For playability and brevity I found that some of this stuff simply had to get cut out.

Now, IF we had gone directly with the results from the prior blog commentators' consensus (none of my alterations), then we could technically have had effects something like this: Pikes in full ranks against infantry get ×4 attacks in the first turn on defense, ×3 in later turns; against cavalry they get ×3 attacks in the first turn and ×2 in later turns.* Pikes in a single figure-rank get ×2 attacks versus infantry in the first turn on defense, ×1 versus infantry in later turns or against cavalry all of the time.

* Visualize: Most of the time, enemies are taking attacks from one lead guy pike-down with a sword, plus one further-back guy with the pike, for 2 attacks per turn. Add another attack per turn on average when someone moves through the pike field; and more on the first turn when that's definitely necessary. Cavalry dial it down a bit from the 25% of hits that would go against the horse instead. This always assumes a rational strategy of opponents hanging back beyond the pike field until there is a gap for them to advance into (i.e., never just hanging out in the pike field taking hits for no good reason).

No matter how we slice it, by D&D man-to-man rules, within the first turn an enemy will be able to get under the pikes and start delivering hits on the pikemen (the pike defense doesn't make the pike unit appreciable harder to hit in BOW scale). So in the interest of brevity, I've basically taken the extremes of the results above and cut the pike rules down to those: ×4 attacks on the defensive interrupt-attack, ×2 for same in a single figure-rank, or ×1 attack in any other situation. This specifically highlights the defensive mechanic of pikes; the model is, like, after the first turn, the enemy has gotten in "under" the pikes, there is a swordfight at the front rank while back pikes are not really usable, and meanwhile further ranks of the enemy hang back out of range until an opening appears. Pikes get the +4 defensive formation to-hit (+1 in BOW) versus everyone, and an additional +2 to hit (also rounded up to +1 in BOW) versus cavalry to reflect their lost AC bonus. Those modifiers are sufficient to score at least some hits against even charging heavy cavalry, and then by giving a morale check in that situation, there is some good chance to turn aside the attack; and the mechanic deals smoothly with huge monsters like giants and dragons (unlike the Chainmail mass rule that simply prohibits any attacks on pikes).

The final published rule for pikes in Book of War winds up looking like this:
Pikemen: Footmen with long pikes have a special defensive advantage: when an enemy first makes contact from the front, the pikes get an immediate free attack. This attack is at double dice in a single rank, or quadruple dice in multiple ranks; with an attack bonus of +1 vs. infantry, +2 vs. cavalry. The enemy checks morale immediately, and if failed, gets no attack. Pikes lose this benefit in any non-open terrain, or when routed. Pikes can also attack enemies up to 1" away, without making direct contact. [BOW, p. 7]

The additional things you see here are a loss of the defensive benefit on non-open terrain or when routed (to give the flavor of pike organization issues and the historical cases of losing when pushed into bad terrain, without creating any brand-new mechanics just for this purpose; see Question #10). And the 1" attack range at the end is both realistic, and a nice way of signaling whether the "interrupt strike" has occurred yet (in synch with our desire to have all information visible directly from the figures on the table; if pike figures are in direct contact with an enemy, then it's past the first turn and the interrupt strike is over). Tactically what usually happens is that pikes get 1" away and make an initial, single attack (from the front man-ranks only), giving the enemy the opportunity to flee away from that challenge. However, if on the next turn the enemy presses the attack, then they'll suffer the whole ×4 attack routine with bonuses, if so committed to that course.

That's as short, concise, and playable as I could make that rule -- I went around with numerous different formulations last fall and got feedback from my primary testers before settling on it. (I think somewhere I have a text file with about a score of different possible permutations.) I've found that it works out extremely well in play, and it even has some nifty "emergent behavior" that winds up playing in ways different than what you might expect at first blush (although I've given some hints in the paragraph above). More on that a little later.

If you want to see it, below you'll find a version of the RGPBattle program with the blog commentators' consensus options all switched in, and a spreadsheet of results for pike attacks in that scenario:

3 comments:

  1. Amazing. That feels like a very satisfactory rule.

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  2. This might bear some further looking into, as my familiarity with defending against a charge comes mostly from accounts of infantry squares vs. horse in the Napoleonic era, but my understanding was that the benefit of a massed wall of pointy things (bayonets in the Napoleonic era, or pikes or spears) is that horses simply would not charge them.

    Cavalry charges would stop short of the wall, as the horse were unwilling to impale themselves. Apparently, one of the main risks to an infantry square was firing too late at a cavalry charge, as the momentum of a dead horse could carry it through the wall (making a breach) where a live horse would stop.

    With that in mind, the importance of charging from a flank and the strength of the infantry square against a charge becomes more clear.

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  3. Joshua -- Thank you!

    Charles -- I think I agree with those observations. It's one possible frailty in the historical end of the simulation, but I did want one rule that would apply smoothly to men, horses, giants, dragons, etc. And for simplicity, the only morale checks that I apply are from actual scored casualties (which are part of the morale-check formula).

    Now, the interesting thing is that it usually winds up playing out as you describe anyway, because the player him/herself is usually unwilling to throw a cavalry unit at a pike square. But admittedly they do have the option of committing their forces in that way, if they so desire.

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