Bastard sword

A bastard sword is a sword that, like longswords, can be used in either one or two hands, giving it its name. It has a longer grip than a one-handed sword and has a relatively short blade for extra precision in the strike. It is also more powerful due to its increased weight.

Use
Bastard swords require the exotic weapons feat in D&D 3rd edition if a character wishes to use it without penalty. In the 3.5 edition it requires the exotic weapon proficiency to wield it one-handed without penalty.

Historical Comparison
Historically, the "bastard sword" was merely a form of Western European sword sized between the single-handed knightly or arming sword, and the larger two-handed longswords. The only functional difference is that the bastard sword could be readily wielded either one or two-handed(whereas the arming sword was designed for single-handed use and the longsword was most effectively used two-handed). Otherwise, these swords were wielded identically to their smaller and larger relations and would require no special training.