Here was a bit cut out of the upcoming GURPS: Technical Grappling. There are several reasons.

1. It’s a grappling book, not a striking book
2. I was using Size Modifier as a direct proxy for height. That’s wrong.
3. First See Rule #1.

Reach, Balance, and Power

GURPS’ rules for reach in combat are generic and fit most purposes. Where more detail is desired, Martial Arts (pp. 98-99) gives additional penalties for attempting to strike or grapple targets from odd postures (grappling the head of a standing man while lying down), and encourages the GM to forbid silly or impossible attempts. When using these rules, consider the following guidelines:

• The arms are attached to the upper torso, and may reach one region up or down from a region in which the upper torso is centered. If kneeling over the lower torso, a human may reach his foe’s upper torso or legs (though one of these will be behind him if grappling a region with two arms).
• The legs are attached at the lower torso, and may grapple anything from the lower torso and below; if Flexible or Double Jointed, the legs may grapple two regions higher then where the lower torso is located; Flexible legs can grapple the entire body if in coincident orientation with the upper torsos in the same hex!
• If considering creatures of different Size Modifiers, treat the arms as reaching from SM+0 to SM-2, and the legs as easily reaching SM-2 and below. If Flexible or Double Jointed, the legs may reach from SM+0 and lower. Likewise, grappling regions get larger as well; on an SM+2 creature, you may only grapple one body region at a time . . . and suffer -6 while doing even that!
• GURPS Size Modifiers are geometric in nature: while SM-1 is 2/3 the height of SM+0, SM+1 is 50% taller! As such, the head of a SM+1 creature is out of reach for a SM+0 human without jumping or superhuman abilities like Long Arms (p. B53).
• The generic penalty for kicking (-2) assumes a torso level kick – presumably the lower torso. Instead, you may kick anything at SM-4 and lower at no penalty, and each SM higher at an additional -1. Kicking to the head is thus -4, while stomping a grounded foe is not penalized!
• You may trade balance for power in any move which carries a DX penalty by trading -1 damage for removing -1 DX penalty (this may not result in a bonus). Thus, a “light contact only” kick to the head may be thrown un-penalized at thr-4; this is suitable for some sporting competitions, but not full-contact events! Flying grappling moves may take the same reduction in Control Points in exchange for being less likely to fall down.

Analysis: Found Wanting

Interestingly enough, TBone just posted to his blog a bit of an idea that seems awfully familiar.

+Peter V. Dell’Orto responded with a really good analysis of why both my idea and TBone’s are not really necessary.

Initially, I thought the same thing as TBone – high kicks should be harder than low ones. After all, we give basically the same advice to novices when teaching martial arts. However, had this section been in the final draft, I think Peter’s analysis would have resulted in its being cut anyway. The “how flexibile are you?” question for people who don’t train to fight is “not very, mostly,” but if you do train, you stretch, or at least get flexible enough that you can do what you need to do, under pressure, when you need to do it. Any athletic activity done without flexibility risks bad injury, so there we go.

Also, a full-power kick to ANY target is delivering a lot of oomph while standing on one foot. I don’t know that falling down is really less likely with a missed low kick as high. Certainly not at GURPS‘ level of resolution.

I’ve come full circle on this rule, and now I’m in Peter’s camp: not needed.