I got 3 videos for everyone. Okay, so on Youtube, there's this fake ninja named Choson Ninja who claims that ninja are Korean and used straight swords. (Straight swords were obsolete by the time ninja appeared, their swords are actually wakizashi blades fitted in katana standards for a faster drawing sword.) Here's his piece o' s**t excuse of a video:
http://www.youtube.com/watch?v=vtUiDxz2Qp8And here's 2 responses from historians and ninjutsu practitioners:
http://www.youtube.com/watch?v=bXSTtL6ygTshttp://www.youtube.com/watch?v=iHXHjJghIWAIn the first response video, the guy who made it is in the Bujinkan, a famous ninjutsu organization that teaches ninjutsu with Iga lineage. (Not really Iga ryu though.) He makes a reference to round holes because Choson Ninja stole the shuriken designs from Togakure ryu, which is the Bujinkan's main art, and said that Korean shurikens have round holes. The second response is a Japanese man who is interested in history as well.