Two pieces of trivia that are in fact related:

• The name “Trench Coat” comes from the heavy, long wool coats that German soldiers wore in the trenches during WWI.
• The Geneva Convention banned the use of knives and blades that had more than two sides.

During WWI, the US issued a tri-cornered knife to soldiers.  The knife was designed to pierce the German Trench Coat.  (A normal blade wouldn’t pierce the coat.)  It was common for men to infiltrate the trenches of the enemy and then use knives to slash the hell out of them.

At the Geneva Convention, the tri-cornered knives were banned.  Although they were good at piercing jackets, they also created wounds that were very hard to stitch.  A knife with one or two blades created a wound that was easier to stitch, thereby allowing more wounded soldiers to live after being stabbed.

Source: Pawn Stars on the History Channel