This is a cinematic technique, usually restricted to cinematic campaigns.
- Technique Name: Whirlwind Attack
- Difficulty: Hard
- Prerequisite: Boxing, Karate, or any Melee Weapon Skill
- Default: Primary Skill-5
- Maximum: Primary Skill
- Damage: Per attack(s)
- Book/Page: Basic Set 232 and GURPS Martial Arts 89
Gun Fu page 10:
- Suppression Fire (pp. B409-410) and Whirlwind Attack (p. 30) are exceptions to these rules.
- Either of these All-Out Attack maneuvers is all you can do on your turn, regardless of special advantages.
- You can use two guns here.
- If you do, you may attack the same or separate arcs or opponents with them.
- Extra Attack (any level) means there’s no penalty for this other than any off-hand penalty that may apply.
- Otherwise, apply any relevant Dual-Weapon Attack penalty that you haven’t bought off.
FAQ[]
http://www.sjgames.com/gurps/faq/FAQ4-3.html#SS3.4.2.20
- You must forfeit all Extra Attacks to perform a Whirlwind Attack.
This is an added rule because MA never said anything like that! It simply said that you took an All-Out Attack maneuver, you can spin in place, and you can attack (including punch, normally C range) everyone within a yard.
That presumably is some combination of AOA Long / AOA Double where instead of getting 1/2 Move you get 0 Move (and all remaining attacks critically missing if one does, plus an inability to use other techniques, or cinematic skills) in exchange for extra attacks.
6 cap[]
Kromm mentioned in 2007 http://forums.sjgames.com/showpost.php?p=489135&postcount=30
- It works just like the melee version, but with bullets: you shoot up to six people in the hexes surrounding yours, provided you have that many bullets.
A maximum of 6 was never listed in MA or GF. This is a retcon, with Kromm defining a breakdown at http://forums.sjgames.com/showpost.php?p=456362&postcount=8
- Maneuver: All-Out Attack (Determined), +4
- Combat Option: Rapid Strike, five extra attacks (a total of six, for the six hexes around you) is -6×5 = -30, but halved for this being cinematic and the user being Trained by a Master or a Weapon Master, -15*
- Drawback: All you can do this turn (no further Rapid Strike, DWA, Fast-Draw, etc.), +1
- Drawback: Can't combine this with other techniques or special skills, +1
- Drawback: Can't step, can only turn in place, +1
- Drawback: Limited to swings at 1 yard in a fixed order against all foes, +1
- Drawback: Multiple critical misses on any critical miss, +1
- Drawback: Must accept random hit location, complete with penalty, +1
"you don't need Trained by a Master or Weapon Master to attempt this at default. Those who lack those traits really ought to be at -20, not -5. But since it's an All-Out Attack that leaves you without defenses, quite likely still surrounded by foes who made defense rolls, we let it slide."
https://www.ravensnpennies.com/gurps101-deconstructing-whirlwind-attack/ links back to it
Deceptive Attacks and Feints[]
also 2007 by Kromm http://forums.sjgames.com/showpost.php?p=454308&postcount=3
- if you can manage feints against some or all of the targets of Whirlwind Attack or Grand Disarm, then you enjoy the benefits of those feints if you hit
- ..
- Whirlwind attack can't be combined with other techniques or with cinematic skills, but there's no inherent prohibition against Deceptive Attacks all 'round. When a rule doesn't say you can't, you can.
This makes sense since DA is a combat option, while Feint is not combined (it happens the previous turn)