One of the core nifty bits of the Judo Throw in GURPS is that you can damage people with it. A damaging throw can be used to inflict (more or less) thrust-ish damage to a location of your choice.
On the other hand, you can also use a grappling skill to obtain a joint lock, and then use Throws from Locks in Martial Arts/Technical Grappling to do freakin’ swing damage to that joint. An original comment in the TG manuscript noted that a throw from a Head Lock (which effectively does 1.5x swing damage to the neck location) is likely the most damaging grappling attack in GURPS.
However, one thing that is missing is a damaging takedown. As anyone who’s ever been knocked down and stunned/winded can attest, getting taken down hurts, or at least can hurt. If a bully (or a giant, or a giant bully) picks you up and throws you to the ground, it can hurt.
I think there are two ways using the rules to try and simulate this.
Damage From Thrown Objects
The first way to do it is to treat certain attacks as effectively throwing the foe to the ground, using the thrown objects rules in the Basic Set (p. B355). If a Trained ST 14 (BL 40) fighter wants to fling his 160-lb. foe to the ground (4xBL), he’ll do thrust damage, at -1 per 2d, rounding down. This is 1d-1 for ST 14.
I’d probably treat this as follows: You must execute a Force Posture Change to force your foe prone, and this should be an All-Out Attack (Strong) . . . but you don’t get the bonus for it, that’s the cost of admission to the thrust damage. You must have (and spend) Control Points to set the max damage, as well as impart any DX penalties to throw him and have him land badly. Your foe may reduce damage with Breakfall.
That’s not a complete rule, but that’s the concept. For most humans, you’re talking about thrust-1 which is basically striking damage.
The other way to do it is to simulate this as a collision with the ground, probably from roughly half the height of either the grappler or the target. Let’s say the target (I’ll get to why in a moment). This would typically be falling from 1 yard against a hard object, which means typically you’ll be suffering based on the falling velocity of 5 yards/sec, so 10 HP x 5 yds/sec x 2 = 1d.
That means that the thrown object or falling rules seem about the same for human scale. Not sure if it matters, then, which you use.
As is usual in the rules, Acrobatics or Breakfall can be used to mitigate the damage from a fall, and breakfall defaults to Wrestling or Judo. Certain games that involve a lot of collisions and being thrown to the ground, like football, hockey, and rugby, might buy a Technique Adaptation perk to allow Breakfall to default to the appropriate Sports skill.
Again, the attacker would spend Control Points to set the max damage.
Attack and Defend, Injury or Stun
In many cases, the damage from a takedown is likely incidental. This would be the plain-vanilla case of a usual Force Posture Change, where you roll 1d-3, and 50% of the time, there’s no impact to absorb. But I’ve seen enough people get landed on, or fall badly, and get winded or even concussed from takedowns that were emphatically not judo throws to desire a mechanic.
Now, this could just be a bad roll on the Grappling Critical Misses Table from Pyramid #3/61. After all, it doesn’t happen every match. I suspect, though, that given how relatively easy it was to take someone down and have it end badly for them when they did not know what they were doing, or anticipate the fall, that most of the time, such a takedown is not damaging because either the grappler doesn’t want to make it damaging (spend CP) and risk hurting a friend or getting disqualified in a competition, or the defender is reasonably trained and can mitigate damage with a Breakfall roll (see Martial Arts, pp. 68-69).
How many HP?
The nice thing about basing the takedown damage on the target is that each character can pre-calculate how much he risks taking when being taken down. It’s just 2 x HP x Falling Velocity/100 from half your height.
For SM +0 critters, that’s 1 yard, which means you will take damage equal to 0.1 x HP in dice. That’s just nice and easy.
First, though, you’re going to want to know if your HP are from weight or grit. Here are some guidelines for this for fleshy critters:
This will set rational limits on how much damage you can take from a fall if your character has HP disproportionate to his mass. Note that rounding conventions make this even easier to figure damage: if you are falling from 1 yard, 7-9 HP takes 1d-1, 10-12 HP takes 1d, 13-15 HP takes 1d+1. That’s about it.
Fleshbag HP are just 2xcube root of weight in lbs, and the velocity from a fall is on p. B431 for non-humans.
If you decide to add your own weight to the fall, an All-Out Attack that has you matching posture, you may claim the +1 per die or +2 bonus for AoA(Strong), and figure HP as if you and your foe’s mass were added together. So if our 250-lb guy wanted to drop the hurt on a 160-lb. foe, velocity stays 5, but weight is now 410lbs, for 15 HP, adding in AoA(Strong) to get 1d+1, +2 for strong, is 1d+3. This can still be mitigated by breakfall, but could be quite painful.
I think in general this rule is for those who really think you should be able to hurt people on a takedown. Like maybe this guy. who notes that you can’t really do a damaging takedown in GURPS with Wrestling.
Having this be a freebie with a takedown using GURPS RAW isn’t probably cool. The disadvantages of being taken to the ground are legion in GURPS, and that’s probably reward unto itself.
Still, being tossed to the ground while (say) wearing 100 lbs of steel should probably suck. Likewise, there are lots of ways to be kinda evil when you do a takedown, which you can maybe model with either a Dual-Weapon Attack or Rapid Strike (the usual way of ensuring you don’t get a freebie in GURPS is to take large penalties to get it done).
Anyway, this was on my list of things to cover for a while, and the comment I linked to above reminded me.
There are a few ways to model it, but it will add some die rolls if you allow it willy-nilly. With Control Points, though, you have to give something up (the CP, by spending them) to injure someone badly, which means you have to work for it.
On, one last thing: I’d only use the Damage From Thrown Objects rule for flinging someone down after a Pickup, when you’re actually throwing them. Otherwise, I’d use falling.