Wednesday, August 5, 2015

A Two-Handed Sword Does 5.5 Points of Damage

Two things -- a recent event in my family Labyrinth Lord game, and a train of thought that crossed my mind during this morning's breakfast -- led me to a realization about weapon damage.

I began running a Labyrinth Lord campaign with my son and wife as players, each controlling two characters. I'm aware it's generally a no-no to double up on characters, but it's working for us in our situation. Anyway, after two of the 1st-level PC's perished, the remaining two found themselves at the top of a deep cistern with a black pudding climbing after them. To my surprise, they had dispatched it in only a couple rounds by firing arrows at it, then hacking at it when it reached the top. Of course I profusely congratulated them on such a fortuitous success (my 7-year old echoed my excitement for the rest of the day), but something didn't seem right. Checking my sloppy handwritten session notes later, I realized that I accidentally was subtracting HP from another monster with half the hit dice.

I suppressed the urge to find a way to bring the balance of the universe back into order (Reduced XP for the remainder of the adventure? Send another one after them?). I knew one of the golden rules of gaming is, "The DM's ruling is final, even when it's a mistake." The pudding was declared dead, and that's that. So then I tried to imagine how I might justify the error: The HP was at least within the range of possibility; I could assume I had rolled five 1's and five 2's when generating the creature, however improbable. I could figure that, since the description of the monster differed a bit from the version in the rulebook, it was a some kind of weakened variant. Perhaps puddings get weak in their old age? Was it poisoned by sewage? One possibility, that had I more forethought I could have scaled its HP downward intentionally to balance the encounter, only briefly crossed my mind before I dismissed it as too "fudgey."

This morning, I was eating cereal at our kitchen table. My son's dice were resting on the table in front of me, and in boredom I began fiddling with them. As I slid a d10 next to a d4 I imagined explaining their purpose to a non-gamer:
"These represent the damage ranges of different weapons. For example, a dagger would inflict 1-4 points of damage. A halberd or something would naturally have the potential to inflict up to ten points."
"But they both do a mimimim of one?"
"Uh..."
I am a big fan of the bell curve in die rolls. My Castles and Crusades campaign uses 3d6 instead of 1d20 for attacks and attribute checks, because the best and worst possible results shouldn't be as likely as results that are in-between. Likewise, why do we use single dice when figuring damage? Under the current system, a pole arm is 30% likely to deal less damage than a dagger's maximum. But if we used, say, 2d4 instead of 1d10, the probability of dealing 3 or fewer damage points lowers from 30% to 12%, while keeping the mean at 5. If you want to raise the maximum back to 10, make it 2d4+2. Now the mean rises to 7, which I'm sure most fighters would appreciate!

When I'm shopping for weapons and I see damage stats, my tendency is to be optimistic; and I'm guessing this is true for many players. We see "1d10" and our inner voices say "up to 10," instead of "average of 5.5".

In a single-die system, remember that you'll see as many minimums as you will maximums and averages. In fact, let's make it an eponymous aphorism:
Raymond's Law of Damage Dice: You are just as likely to roll a 1 as you are an average result, and it will never happen at a convenient time. 
 The reason you're attacking something is that it's trying to hurt you. There is never a good time to roll a one. But it will happen. And even if you wield a 1d10 weapon, you will roll that one 10% of the time.

How does this tie in with the Black Pudding anecdote? It has to do with scaling adventures. When stocking dungeons, why must a GM roll random HP for its inhabitants? Take advantage of the weakness in damage rules by manipulating monster HP to suit a party's strength at their worst. 

If a party carries no weapons with magical bonuses and an average strength mod of zero, lower monster HP toward its statistical minimum. The stronger the party, the more range you can allow in monster HP. This makes the most sense in low-level adventures, where a difference of one or two on a damage roll can mean life or death of a PC in one round. I generally don't advocate fudging results during combat, but at least you can level the playing field by ensuring that one-shot kills are equally likely for both PC's and their enemies. As PC levels increase, the variance in percentage of total HP lost in a single shot grows smaller.

And if you're a player, remember to guard yourself with a knowledge that you will roll 1's more often than you instinctively suspect. 

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