Useable Weapons in One handed combat:

Primary: A character may use any weapon that he meets both PS and MD scores for, in his primary hand.

Secondary: A character may use any weapon that he meets both PS -2 and MD -2 scores for in his secondary hand, if primary hand is not used to attack (may occur due to grievous injury, or some other reason such as cursed weapon). These penalties account for a character's secondary arm being somewhat weaker and less coordinated than his primary hand.

If you fail to qualify to use a weapon based on PS or MD scores, you can still use it, as per existing rules, without MD or rank modifiers.

Primary: Any weapon a character qualifies for with a -2 penalty for both PS and MD can be used in the primary hand for two handed combat. This rule makes a person who just barely qualifies to use a weapon one handed, unable to fight two handed style with that weapon. No weapons that can be used with both hands on the weapon, such as Battle Axe and Claymore can be used in combination with a second weapon in the secondary hand.

Secondary: Any weapon after qualifying with a -4 penalty to both PS and MD. Ambidextrous characters are considered to have two primary hands, and both weapons must qualify under the primary hand rules, -2 PS, -2 MD.

To Hit penalties apply as stated in Strike Chance Modifier Chart.

-20 Secondary Hand

-10 Multiple Strike Primary Hand

-30 Multiple Strike Secondary Hand

-10 Multiple Strike Ambidextrous

2 Hand Fighting Skill (Max rank 5)

When a character with the two handed fighting skill fights with a qualifying weapon in each hand, he decreases the strike chance penalty of his primary hand 2% per rank and secondary hand 4% per rank. Ambidextrous characters get the penalty decreased 2% per rank for both hands. The 2hand fighting skill can never bring the strike chance penalty higher than 0. At rank 5, the average character would have no penalty to his strike chance with his primary hand and only a -10 penalty with his secondary hand. An ambidextrous character would have no penalties for 2 handed fighting style at rank 5. At rank 0, a character can fight with weapons in his secondary hand that meet the -2 PS and -2 MD requirements of the primary hand. Ambidextrous characters get no benefit from 2 Hand Fighting Skill at rank 0.

Experience Point Cost

Rank 0 1 2 3 4 5

2 Handed fighting 300 200 500 750 1000 1000

The EXP cost is just slightly higher than Unarmed combat costs.