Long Axe martial art?
 

For the Anglo Saxon Thegn/Thane, Viking Huscarl, and early Knight the main weapon was the long axe, as Low Tech said it was known variously as the Viking/Norwegian/English/etc axe. The Poleaxe was probably an evolution of this to deal with opponents wearing plate. Martial Arts provides for the Poleaxe style but not the earlier long axe, has any supplement suggested anything or has anyone homebrewed something or is the matter already settled on just using the Poleaxe style?

Re: Long Axe martial art?
 

IIRC, there's a Pyramid article which includes an Yrth axe-fighting style.

This is a fantasy axe-fighting style that I've adapted from stuff I found online. It might be a start for developing a more historical style.


Dwarven Axe-Fighting
2 or 7 points
This is a fantasy martial art for use by dwarves and other short, stocky creatures that like axes and infighting.
Note: There is a 5 point unusual background for a non-dwarf to start with this style, this Unusual Background increases if you are from a race that is hostile to dwarves.

Skills: Axe/Mace, Shield.
Cinematic Skills: Blind Fighting; Immovable Stance; Power Blow; Breaking Blow; Mental Strength.
Techniques: Lantern Fighting; Shield Snatch; Shield Press; Targeted Attack (Knee).

Optional Traits
Advantage: Damage Resistance (Limitation: Tough Skin, -40%); High Pain Threshold; Unusual Background (Non-Dwarf).
Skills: Armoury (Armor, Blades, or Melee Weapons); Brawling; Fast-Draw (Axe/Mace); Thrown Weapon (Axe/Mace); Two-Handed Axe/Mace; Wrestling.

This one I developed based on martial arts training and historical research, although it's based on something I found online:

Viking Combat Training
3 points
This “style” represents European Migration-Era (5th to 11th c.) Viking foot combat training. While most closely associated with Scandinavian sea-raiders known as Vikings, it might be appropriate for similar Western or Northern European sea-borne raiders like the Angles, Jutes, or Saxons.
The signature weapons of this style are the axe, shield, spear, and two-handed axe. Those who could afford the cost also used slashing broadswords. Vikings were highly mobile, either riding horses or sailing ships into battle. In both cases, they would dismount prior to combat, entering battle on foot.

Skills: Wrestling; one of Axe/Mace; Broadsword; Spear; or Two-Handed Axe/Mace. One of Crewman/TL (Rowing or Seamanship) or Riding (Horse).
Techniques: Armed Grapple; Choke Hold; Retain Weapon; Unbalanced Attack (Axe).
Cinematic Skills: Breaking Blow; Kiai; Power Blow.
Cinematic Maneuvers: None.

Optional Traits
Advantages: Allies; Combat Reflexes; Claim to Hospitality; Enhanced Block; Enhanced Dodge; Enhanced Parry; Fearlessness; High Pain Threshold; Social Regard (Feared); Status; Temperature Tolerance; Terrain Adaptation (Ice/Snow or Shallow Water), Wealth.
Disadvantages: Berserk; Bully; Callous; Code of Honor; Compulsive Behavior (Carousing, Dueling, Wanderlust); Duty; Greed; Intolerance; Odious Personal Habits; Reputation; Sense of Duty; Social Stigma; Vow.
Skills: Additional melee weapons; Autohypnosis; Boating; Brawling; Knife; Intimidation; Literature; Meteorology; Poetry; Shield; Survival; Swimming.

Re: Long Axe martial art?
 

I think I'd look at both the Pollaxe style (dropping the Games skill and swapping Polearm with Two-Handed Axe/Mace, which I believe is the main skill that the Long Axe is used with in GURPS) and at European styles that include Two-Handed Axe/Mace... though I'm having trouble finding any that have it as a required skill instead of an optional skill. Taking Early Medieval Knightly Mounted Combat and either adding Two-Handed Axe/Mace or using it to replace one of the existing weapon skills should work. Of course, swapping out skills also usually means altering techniques, but those two probably don't need a lot of changes there.

Pursuivant's 'Viking Combat Training' looks pretty good for this, also.

Re: Long Axe martial art?
 

For actual Vikings, I'd have Crewman (Rowing) be a primary skill, with Riding (Horse) an Optional Skill.

Re: Long Axe martial art?
 

I'd also potentially add Bow, Fishing, Merchant, and Thrown Weapon to optional skills, although that makes it even less of a Martial Arts "style" and more of a character template.