Cost: 5 points

Ambidexterity is a physical, mundane advantage described in Basic Set, p. 39.

Kromm QuotesEdit

Sean Punch has commented on Ambidexterity in the following posts to the SJG GURPS Forums:

re pricingEdit

in 2004

it doesn't give extra attacks, or affect the vast majority of tasks that need two hands, or really do much of anything most of the time. We were thinking of even making it a 1-point perk.

re ParryingEdit

September 2006

You get one active defense per hand before you run into the multiple-defense penalty (typically a cumulative -4 per parry after the first with the same hand or weapon). The scores used are: Block or Parry w. master hand = skill/2 + 3

Block w. off hand = skill/2 + 3

Parry w. off hand if using an unarmed combat skill or Main-Gauche = skill/2 + 3

Parry w. off hand if using any other Melee Weapon skill = (skill-4)/2 + 3 w/o Ambidexterity or Off-Hand Weapon Training, or skill/2 + 3 with one of those abilities

September 2007

II. Off-Hand Penalties. There is a -2 on all one-handed parries with the off hand unless one of the following applies:
You have Ambidexterity.
You have Off-Hand Weapon Training with that weapon (this is a technique in the Basic Set but a perk in Martial Arts).
You're using a skill that explicitly ignores off-hand penalties; e.g., Karate or Main-Gauche.
If any of those apply, then ignore the -2.

Off-hand penalties never apply to two-handed parries or to blocks.

A notable shift here is in 2006 he specified the -4 is ignored for "unarmed combat" whereas in 2007 he only specified "karate". The latter is more consistent with the rules, since only karate makes explicit mention of ignoring the -4, albeit only in regard to punches, not parries.

re Extra ArmsEdit

2006? in 2009 here Der Wanderer wrote:

I asked this question to Kromm about 3 years ago, so here are his answers:

Ok, assuming our hero has 4 arms (Extra Arms 2)... How many of his four Hands, are off-hands?

Originally Posted by Kromm
Half of them.

Does Ambidexterity affect all Hands, removing off-hand penalties from all?

Originally Posted by Kromm


Eveything is at -4 for using multiple hands at once. You get one master hand and everything else is at -4 for the off hand. Thus, it's -4/-8/-8/-8. Anything worse and Extra Arms wouldn't be worth 10 points/level.

Treat abilities that remove these penalties normally. Those that remove the -4 for multiple hands at once cost the usual amount and remove up to -4, for at best 0/-4/-4/-4. Those that remove the -4 for off hands cost the usual amount and remove up to -4, for at best -4/-4/-4/-4. Getting both can remove all penalties.

2013 post expressed confusion:

I don't know how to interpret "Those that remove the -4 for off hands cost the usual amount" -- is the usual amount a flat 5 for Ambidexterity, or 5 per hand? Similarly, is it a flat 1 for Off-Hand Weapon Training, or 1 per hand?

Vicky molokh pointed out here a comparison to the Bush Robot from GURPS Ultra-Tech and GURPS Transhuman Space

The Bush Robot has three arms but only one Ambidexterity, and its arms are interchangeable. Thus it should be enough. (I seem to recall that a multi-armed entity is assumed to have an 'on-side' and an 'off-side' by default, but I can't find it.)


PK quotesEdit


I was under the impression that if you had multiple arms, half of your arms (round down) are your "good" arms and the other half (round up) are your "off" arms. But I don't have my books at the moment.


Yeah, if you have four arms, two are "good arms" and two are "off arms" and Ambidexterity makes all of your arms "good" ones.

See AlsoEdit