Decapitation

Decapitation is a concept described in several places, with strange rules. In most cases, losing a head is completely lethal.

Example Exceptions

• Target can't be killed by mundane means (see Unkillable)
• Head doesn't contain brain
  • Robots with heads that only contain sensors (which become merely blinded when decapitated)

Classic rules

FAQ makes reference to a change at http://www.sjgames.com/gurps/faq/FAQ4-3.html#SS3.4.5.4

3.4.5.4 What happened to the Neck hit location?

The rules are the same as for Third Edition, except that there is no automatic or resisted decapitation anymore. It can only happen as a special effect of an ordinary killing blow to the neck.

The reason why is that decapitating freestanding foes with a hand weapon is simply not realistic. It's fantasy-novel and action-movie "realism," sure, but nothing to do with real-world fights. There's a reason executioners used great, huge, heavy swords on stationary targets with their necks on blocks

The "resisted" decapitation refers to making a HT check to prevent it. The circumstance this happens is defined in 2 places:

• B248 "If the neck takes full hit point damage from an edged weapon"
• Compendium 2 "Any cutting blow that does over HT damage"

not lethal

B423 Instant Death has led some to assume wrongly that decapitation MUST be lethal

Decapitation, a cut throat, etc. can kill anyone, regardless of HT and HP.

If a helpless or unconscious person is attacked in an obviously lethal way, he’s dead

First to keep in mind is that "cut throat" is a condition mentioned at the same time, and indeed, decapitation is merely a subset of that.

There's no special rule there at all: just that someone is dead if hit with an "obviously lethal" attack.

Just as a "cut throat" can fail to meet an "obviously lethal" standard, decapitation can fail to meet that standard too.

"Just assume that he drops to -5xHP." makes sense as a policy if the minimum possible injury is enough to bring them there. If it does not, then it is not "obviously lethal".

The instruction "don't bother to roll for damage" is also clearly a problem in some situations even when it will be lethal regardless of outcome, such as when Overpenetration occurs. Using B408's example, Ira Gray might be hit with an obviously lethal attack (say the 7d round hit him in the EYE instead of the vest) but the damage would still need to be rolled to determine how much would get through to the VIP behind him.

While this might make sense for normal humans, given how GURPS deals with some foes who are very tough and some who are very weak, this is a guideline which should probably be ignored in complicated games, using existing rules for determining death to resolve it.

"Just assume he drops to -5xHP" for attacks doing less damage than what's required to get there is often fine when there's no time limit and you can attack an unlimited amount of times (example: you have 10 minutes to hack up a corpse) but is an unfair assumption when the time taken to kill 1 foe matters (ie another foe is running to the rescue to try and stop you finishing them off).

• in cases where the attacker is not being attacked (no other combat going on, body remains unconscious) they could just get bonuses to hit (nearly guaranteeing it, perhaps automatic success if effective skill is 15+ per LRAB) allowing them to focus on getting maximized damage bonuses (Springing Attack and AOA:strong) to quickly end someone.

Deadly Heads

Some non-magical creatures remain dangerous even when decapitated. Vipers (such as rattlesnakes) and cobras can still bite and inject venom after they've lost their bodies--something any good snake handler or survivalist should know.

This could be replicated in two ways:

• B423 Dying Actions if the GM considers instant decapitation "sudden" but not "thorough". Doing a worry against something you've already bitten seems reasonable, but doing a Move and Attack to Bite probably would not, since your torso is no longer attached to your head to propel it through space
• don't consider decapitation to be instant death: allow it to happen at thresholds lower than a failed HT check to survive, such as 2xHP (implied by B54's Extra Heads formula) which is double the amount needed for 3e's health checks. Alternatively, require the Spine location (and 3 DR) introduced in Martial Arts to be targeted and suffer double the amount needed to cripple it: destroying the cervical spine is nearly enough to decapitate just as destroying the lumbar spine would be enough to cut someone in half
  • for normal animals, the combination of suffocation (brain is no longer connected to lungs) and blood loss is going to bring someone there.

When it Doesn't Kill

• Independent Body Parts (Detachable Head) allows one to continue moving and acting with a removed head--this can be horrifying or comedic, depending on the delivery.

See to the IBP page for details. Note: This HALF the the 2xHP requirement seen below from Extra Head. See also: Dismemberment.

• Extra Head on B54:

cannot suffer more than 2 x (your HP/number of heads) points of injury from any single attack to your head or neck.

• for example, 2 x HP10 = 20 injury. 20 divided by 2 heads = cap of 10 injury.
  • this could be taken to imply the maximum amount of injury that could be suffered by an attack to the head (face or skull) or neck of a 1-headed being with 10 HP could be 20.

A critical head blow that would normally kill you simply destroys that head, inflicting the maximum injury noted above and crushing, severing, or exploding the head (GM’s option)

This cap is lowered via the Extraneous limitation, which is actually beneficial

A single blow to an Extraneous head can do no more than HP/(1.5 x number of heads) points of injury

• for example: 1.5x2 heads = a divisor of 3. 10 HP divided by 3 is 3⅓. It's unclear whether to round that cap down to a loss of 3 HP or up to a loss of 4 HP.
  • extrapolated for a 1-headed being who lacks a brain, dividing 10 by 1.5 results in 6⅔ (similarly unclear whether to round that up to 7 or down to 6)

This probably means Extraneous could be split into an enhancement and a limitation, similar to how Insubstantial Only could be split into Affects Insubstantial and Not Substantial.

The injury cap is influenced by whether or not extra heads have a brain or not.

The pattern where maximum injury sufferable reduces with backups is apparent in rules for extra limbs. These are not found on B53/B55 so many are likely unaware of them. They are found under Crippling Injury (B420) continuation on B421 called Crippling Extra Limbs which effectively also includes Crippling Extra Extremities:

a crippling blow is injury over HP/(number of limbs of that kind);

e.g., if you have four arms, injury over HP/4 cripples an arm.

a crippling blow is injury over HP/(1.5 ¥ number of extremities of that kind);

e.g., if you have four feet, injury over HP/6 cripples a foot.

The condition in both cases is "if you have more than two", so it doesn't make it harder to cripple foes with One Hand or One Arm.

Further up the page it is clarified that a wing or striker or tail is a type of limb, while a tail or fin or extraneous head is considered an extremity.

Due to "can never cause more injury than the minimum required to cripple" this is a survival advantage. Presumably crippling will always result in a loss of at least 1 HP since that's the minimum resolution of injury possible under basic rules.

In rules which allow <1HP fractions/increments this could be different. For example if you allow 0.1 increments: with a 1 HP creature, it requires inflicting more than 1/2 (0.5) it's HP to cripple a limb. The minimum resolution for this is 0.6 which is how much HP they would lose, leaving them with 0.4 HP.

• conversely with a creature that has 10 legs: it requires more than 0.1 HP to cripple, so 0.2 HP is lost
• with 11+ legs: 0.1 HP would be adequate to cripple: so that's all the HP that can be lost.

These rules represent a geometric effect of "Extra X" which supposedly balances out: the benefit of losing less HP from a disabled body part is balanced out by that body part being easier to disable.

There do not appear to be rules for having extra limbs without making those limbs easier to cripple or injuring the person less with their destruction. Or balanced rules for having some limbs being easier or harder to destroy than others. Arm ST might be considered to buy up HP for both purposes while Weak might be considered to buy them down. This might apply to hands. There is no equivalent of this for legs/feet.

when killed

B399 (under Neck):

The GM may rule that anyone killed by a cutting blow to the neck is decapitated

B552 (note 9 for the Neck):

At the GM’s option, anyone killed by a cutting blow to the neck is decapitated!

This is functionally pretty silly, because it is possible to be killed by merely 1 penetrating damage which brings your HP low enough to cause a HT check which is failed.

Instead, injury should be capped as per extra head, and it should require targeting the SPINE and severing THAT to cause decapitation.

B423 should be remembered, of course: failing the HT roll by only 1 or 2 is not instant death:

"your internal injuries might kill you even after you stop bleeding"

So penetrating damage 1 reducing it to a HT check threshold is not always a guarantee if the HT check fails, it has to fail by 3+

The only exception is when you reach auto-death threshold (-5x HP) in which case there is no HT check at all.

how to stop it

B61 mentions an immunity under No Neck:

cannot be decapitated

This is probably a bit extreme. Even neckless creatures presumably have some kind of tissue connecting their head to their torso. It should probably just be much more difficult to do, because the connection is harder to target and probably muck thicker.

In their case, severing the thoracic spine would serve a similar purpose to detach the head from the legs.

It probably just means there is no way to detach the head from the arms without detaching the arms from the torso.

Taboo combinations

Zombies 82's Headshots and Other Violence mentions that Cutting to Neck can be taken as a special Vulnerability but that zombies with Detachable Head won't have this flaw.

External links

• https://greyson.conlang.org/2019/09/09/thoughts-on-decapitation-in-gurps/ by GreysonWHY aka Raekai as pointed out here