[Martial Arts] Would this be a valid skill adaption perk?
 

One of the standard longsword techniques taught for use against an armored opponent in the historical manuals is the "murder stroke", where the swordsman holds the longsword by the blade and uses the cross or pommel as a mace/pick. It is actually a rather effective technique because longswords are grip-heavy and end-up weighted much like a mace or pick when used this way (and it is much easier to not cut your hand while doing this than one might think). MA addresses this under the hook technique, allowing for a swordsman to hold the sword by the blade and use the cross as a hook (also historically attested), but requires use of the Two-Handed Axe/Mace skill instead of Two-Handed Sword because the weapon characteristics change so much (there are no rules for using the sword like a mace or pick, but it seems simple enough to just change damage to cr and add +1 to swing damage).

My question is, instead of making a swordsman take skill points in Two-Handed Axe/Mace just for using this technique, would it be valid to use this perk: Skill Adaption (Two-Handed Axe/Mace Defaults to Two-Handed Sword for using a Two-Handed Sword held by the blade)? Or is this too powerful for a Skill Adaption Perk? It would, presumably, allow the swordsman to use his sword like a two-handed mace for attacking, parrying, hooking, etc., which does seem rather good for 1 point, but it also would not help him with an actual mace, pick, axe, or polearm default. Alternately, would you require multiple perks: one for attack and one for defense? Or maybe one for attack, one for defense, and one for every additional technique you might want to use (like hook)?

Thoughts? Thanks!

Re: [Martial Arts] Would this be a valid skill adaption perk?
 

I'd certainly allow it. Especially considering that you'll usually also have to buy Grip Mastery in order to use it effectively without a Ready maneuver.

Re: [Martial Arts] Would this be a valid skill adaption perk?
 

It depends almost entirely on what the default _is_. If it defaults to base Skill it's too powerful, allowing you two skills for 1 pt.

If the default is -4 or so it's only barely useful. You'd have to have Two-handed Sword at DX+4 for the Perk to be better than buying Two-handed Axe/Mace directly.

So what is the default?

Re: [Martial Arts] Would this be a valid skill adaption perk?
 

The murder stroke isn't a Technique in the GURPS sense. It's just a strike with Two-Handed Axe/Mace, but performed with the cross of a sword.

I disagree with your premise, though. It's not giving you two skills for the price of one, it's allowing another use for the Longsword. I don't think the OP was suggesting he be able to fight with an actual Greataxe using the Two-Handed Sword skill (that would be Weapon Adaptation).

Re: [Martial Arts] Would this be a valid skill adaption perk?
 

With the Skill Adaption perk as written there is no additional penalty, basically you get to use one skill in place of another in a limited set of circumstances. The RAW is on MA pg. 51 and it seems to grant a lot of GM lattitude. An iconic one is Skill Adaption (Kick Defaults to Acrobatics), which allows kicks at Acrobatics-2 (just like Karate and Brawling) but does not give damage bonuses for high skill. Likewise, Clinch is Skill Adaption (Wrestling default to Boxing for standing Grapples).

Re: [Martial Arts] Would this be a valid skill adaption perk?
 

Correct, it would be limited to a Two-Handed Sword and represent the fact that this kind of grip and attack is part of Two-Handed Sword training in some schools, but use of a two handed axe, mace, or pick is not.

Re: [Martial Arts] Would this be a valid skill adaption perk?
 

That's exactly the sort of thing Skill Adaptation is for.

Really the only reason you might think otherwise is if you wanted to swing anything other than a reversed sword with your two handed axe swing, by the RAW you'd have no particular default, and might be totally incompetent, which seems a little odd. I might require Two Handed Axe/Mace at DX as an additional prerequisite for the perk. That would ensure you'd have some minimal level of competence with something that wasn't a sword in the same grip, preventing the worst cases of unrealistic silliness, and costs another couple of points, offsetting any arguments about it's way too cheap.

Re: [Martial Arts] Would this be a valid skill adaption perk?
 

I thought so, but I just wantef to make sure I was not missing something--like being too broad in the skill's application.

As a player that would seembfair to me--2 or at least 1 pont in Two Handed Axe/Mace definitely makes sense from a flavor/realism perspective.

Re: [Martial Arts] Would this be a valid skill adaption perk?
 

Disregard what I said. I have apparently confused two different Perks. I can only plead distraction due to my beliefs about what a stupid idea this technique is. :)

Re: [Martial Arts] Would this be a valid skill adaption perk?
 

Demonstrating why this is not a stupid idea for a technique may be a bit off topic, but it is my thread, so here goes:

I know it seems like an odd technique, but it really is commonly depicted in the manuals, usually without gloves of any kind. These are manuals which were used for real, life or death techniques made by recognized masters. But beyond this, many HEMA martial arts practitioners have demonstrated that even with a paper-cutting sharp blade you can do this without cutting your hand--you just need to make sure your hand does not slip. Here is one video that demonstrates this conclusively (I have done this with a moderately sharp blade as well):

https://www.youtube.com/watch?v=vwuQPfvSSlo

In this video he starts really demonstrating the blade sharpness and technique at about 2:00.

Here is a link to another video where the founder of ARMA demonstrates the effectiveness of this technique on a sparing partner in period accurate Gothic plate:

https://www.youtube.com/watch?v=vi757-7XD94

They start the actual sparing a little after 2:00 minutes in this video, and in this one the guy in armor gets stunned and knocked down by a few blows from a murder stroke and his helmet even gets dented.

This really is an effective technique with minimal danger to one's hands and it is very useful against armored opponents due to the ineffectiveness of cutting and stabbing against an active opponent in full plate.