Ambidextrous reduces attack skill penalty when wielding two or more weapons. Attack skill penalty from wielding multiple weapons depends on the length of the weapons.

When a unit wields multiple weapons, it normally suffers a penalty to its Attack Skill. This penalty is calculated by adding up the lengths of all weapons the unit is wielding. The ambidextrous ability counteracts this penalty, allowing the unit to use multiple weapons more effectively.

Let's consider a unit with the following attributes:

• Base Attack Skill: $12$
• Ambidextrous: $2$
• Wielding: Short Sword (length $2$) and Dagger (length $1$)

Without Ambidextrous:

• Total weapon length: $2 + 1 = 3$
• Attack Skill penalty: $-3$
• Final Attack Skill: $12 - 3 = 9$

With Ambidextrous:

• Total weapon length: $2 + 1 = 3$
• Attack Skill penalty: $-3$
• Ambidextrous reduction: $2$
• Remaining penalty: $3 - 2 = 1$
• Final Attack Skill: $12 - 1 = 11$

In this example, the Ambidextrous ability has reduced the dual-wielding penalty from $3$ to $1$, resulting in a higher final Attack Skill.