Dodging & movement

Talysman has been discussing house rules for dodging. This was one of his proposals:

A character can try to dodge an attack from a single opponent per round if the character’s Move rating is higher than the opponent’s Move rating. The character takes damage only if the damage is greater than a 1d6 roll.

The essence of this rule is a form of variable damage reduction. Assuming d6 damage, since this is OD&D, this means that characters with higher movement scores (compared to an attacker) will dodge 21 out of every 36 attacks (this is based on enumerating all 36 possibilities), and damage taken has an expected value of approximately 1.94 (compared to the expected value of 3.5 damage in the case with no dodging).

I don’t love the necessity of another die roll for the dodge, but I am intrigued by the idea of basing some form of damage avoidance or dodging on comparative movement scores, as that fits thematically and potentially makes encumbrance that much more important. Yes, mathematically it is always possible to model any kind of defense as a bonus to AC, but that also feels somehow unsatisfactory in this domain (and tends toward systems with constructs like “flat-footed” to account for those cases where agility would not come into play).

Rather than rolling a die for the dodge, why not give an explicit damage reduction based on the difference between the two movement scores? That is, a character with move 12 would have a DR of 3 when attacked by an enemy with move 9. No extra dice rolls required, and the expected end result is somewhat similar. Any damage result less than this threshold would indicate a successful dodge. This DR would only apply to melee combat (though I could see a class special ability extending it to missile attacks as well, perhaps for a martial arts class like the monk). This also has the added benefit of distinguishing between an attacker with move 9 and move 6 (which would be handled identically in Talysman’s system, assuming the defender had a movement higher than 9). This also means that characters with very high movement rates would be virtually immune to the attacks from slow creatures. This is not necessarily a problem, though it would be reasonable to cap the dodge-based DR (perhaps at 4 or 5) to maintain a higher level of risk.

I’m not sure I would actually use a rule like this in play, as I’ve found such added defense rules to be particularly easy to overlook in the heat of combat, but that said this form of comparative damage reduction seems rather attractive.

5 thoughts on “Dodging & movement”

1. Talysman the Ur-Beatle

Basically, I picked a d6 over a flat DR rating or one based on a table comparing Move rates because I think of it as a temporary hit die, rather than DR. Also, when I use modifiers, I tend to stick to “one of something”: one point, or one die. It’s easy to remember. I never would have thought of varying the resistance based on degree of difference, because it seems like an extra step that’s going to come up a lot. I guess it all boils down to which you think is easier: rolling a die, looking up speeds on a table, or maybe subtracting Moves and using the diff’s as DR. I prefer the first, others are going to prefer the other two.

1. Brendan Post author

@Talysman

Yeah, the logic makes sense, and it’s easy to remember, though I think rolling an extra hit die potentially for every enemy attack is a bit mechanically heavy. Even the comparative method might be a bit too much work, but I do like the idea of integrating the movement score into more situations (even though I don’t even use the traditional movement score anymore; instead, I use Nd6 contested rolls adjusted by armor and encumbrance penalties, with 3d6 representing the basic, unencumbered human).

2. Gus L.

I have noticed that even one or two points of damage reduction make a big difference – even using variable damage. It’s hugely game changing. It would make high dex, lightly armored fighters/thieves absolute combat monsters at higher levels, where big hp pools and attrition are the rule and hit chances are high. I can see a 1 or 2 point reduction as a feature for some kind of special duelist or kung fu class. Maybe even for a demi human race (automatons, rockskined dwarves?), but it would be a defining feature of some special person/thing not a general mechanic.

1. Brendan Post author

@Gus

Yeah, absolutely. This sort of mechanic would allow lightly armored warriors or burglars to waltz around slow monsters with much less chance of being hit. Of course, fast monsters also become even more terrifying. I do think this would be a very impactful mechanical change.

1. Gus L.

I am just thinking it’s something to be careful with, and ask what it does:
1) Makes armor less important.
2) Makes wizards and thieves better melee fighters, especially at higher levels.
3) Lengthens combats
4) Flattens melee damage
5) Makes spells comparatively more dangerous
6) Makes entangling, grappling and backstab more viable combat tactics.

Thus I’d say it provides an exciting and new element to combat without a great deal of math/steps, but has some huge potentials for game changing in arguably negative ways. It might be a good general rule for a game where armor is very rare or weak (cave men, darksun etc.) It is less game changing where damage can be higher or AC can run better then 2 (carcosa dice, ad&d, b/x), and it encourages melee by non-fighters.

Now I still like the option of speed based damage reduction as a special ability. Maybe even simply as a specialty for unarmored or lightly armored warrior types, maybe as a class based one. For monsters it should also be selective – naked weak humanoids should lack it while things like wraiths or insect men would have it.