Originally Posted by
Blur
That Would be considered a Tanto
A tantō (短刀?, "short blade")[1][2] is one of the traditionally made Japanese swords[3] (nihonto)[4][5] that were worn by the samurai class of feudal Japan. The tantō dates to the Heian period, when it was mainly used as a weapon but evolved in design over the years to become more ornate. Tantō were used in traditional martial arts (tantojutsu) and saw a resurgence of use in the West in the 1980s as the design made its way to the US and is a common blade pattern found in modern tactical knives.
Wikipedia ftw