Katana, Double Bladed
From D&D Wiki
Although, the double bladed katana looks like a normal katana it has two blades as opposed to one. The blades are parallel to each other. The two blades are any where from 1 - 2.5 inches apart from each other. a trip can be made, and if the check fails the user can drop the blade to avoid getting hurt from the opponent it is wielded against The purpose of the two blades is to catch the opponents weapon and disarm them. In addition, the wounds that are made are close enough together that Very few have mastered the double bladed katana. The forging of the blade takes double the time because both blades need to be perfectly parallel, and balanced. Also the cost for a they are hard to heal with ordinary medicine. It takes much skill to master because the chance of one untrained getting accidentally hurt is doubled double bladed katana is doubled. It is not treated as a double weapon therefore, the two weapon penalty does not apply.