Is there an offhand?

[0-hr]

A character needs to fight with a sword in his left hand. Is there a penalty for that?

The right hand is empty and (by default) I'm assuming he is right handed unless everyone in D&D ambidextrous.

Is there an off-hand penalty when just using one weapon for a single, normal, attack?

 

[Patryn of Elvenshae]

Technically, yes.

You take a -4 penalty on attacks made with your off-hand and apply only 1/2 your Strength bonus.

It's a rule that appears only in the glossary, which I think is a perfectly ridiculous place to introduce new rules.

An attack made with the off hand incurs a -4 penalty on the attack roll. In addition, only one-half of a character's Strength bonus may be added to damage dealt with a weapon held in the off hand.

I generally ignore this rule.

 

[Li Shenron]

If he's right-handed, his lef-handed attacks would be "off-hand" and receive a -4 penalty to attack rolls and only half bonus to damage from high strength (if he has a strength penalty, it is not halved).

IIRC it used to be in the combat chapter of the 3.0 PHB, or otherwise it was under the Ambidexterity feat description. Since the feat doesn't exist anymore in 3.5, it's possible that this rule was accidentally deleted.

 

[Dross]

I generally ignore this rule.

I actually like this rule somewhat.
(To my knowledge) In history soldiers were always taught to weild weapons in thir right hands and sheilds in their left. Many/most castles were designed to take advantage of this with their stairwells. Keeping this allows the posibility of some interesting situations.

Meh, make a decision, you are right (although technically the Patryn and Li are right).

Just make sure that every player notes the handedness of their PC.