That's NO knife!
It's a kind of an masterpiece asian shortsword variant
put some knowledge to your head instead of "trolololo"
EDIT: The wakizashi is a traditional Japanese sword. It is shorter than the katana, which was well known in the beginning of the 17th century as a kodachi sword. The two swords were always carried together: the wakizashi finished off the work of the katana sword. Such a sword could be from 30cm to 60cm (12 to 24 inches) long. A small version was called a "ko-wakizashi", a longer one was called an "o-wakizashi". (wiki)