Ok, this is just something we played with as a house rule in third ed since it was illogical that you would need an edge like ambidexterity in order to use your off-hand in any usable fashion without getting a penalty since ambidexterity is quite rare (no matter how cheap it is in SR4).

Off-Hand skill
An Off-Hand skill is an exotic weapon skill and cannot be used by the dominant hand, it is something the character has specifically trained to do with his off-hand to be as effective as his main hand (or in some cases even better).

Examples for this skill could be:
Off-Hand Cybergun, Off-Hand Laser, Off-Hand Pistol, Off-hand Throwing

When using twin guns in this way you follow the usual rules for splitting dicepools and reducing the pool by -2.

Umm. What exactly does this rule do?

As written, it seems to let you take another skill that functions exactly the same as the normal one, include a -2 penalty which I assume is the -2 off hand penalty when you split pools.

So in other words, a skill that you would never ever need if you took the base skill. That may not be what you intended, but could you explain further what it is you did intend?

Anarch--I think the plan is to allow characters to use weapons in their off hands but not necessarily at the same time. Picture a street sam with pistol in one hand and katana in another, he melees and kills his target. Then on a second pass, shoots a fleeing guard. The plan is basically just to allow off-hand use without switching hands...

I don't see the situation happening regularly enough to warrant it for my characters, but results may vary...

Actually, ambidexterity is a specific example given for innate qualities that can only be bought at chargen.

Increasing the skill clutter is a bad idea, though - SR4 simply assumes offhand training as integral to normal skills.

Darn. Overlooked it.

I´m using the Off-Hand Specialization in my game, not quiet as goog as Ambidexterity, but this way, you can even the scores for some skills even if you do not have the positive quallity