Four Edge Dagger

Cross-section daggers ground with four edges instead of two. The extra facets make the blade rigid along its length, which is the same reasoning behind the old rondel and stiletto designs meant for thrusting through armour. Today these are display and collector pieces, forged in Damascus and stainless with brass or bone fittings and a fitted sheath. Multi-edged blades are restricted in several US states, so check your local rules first.