Continuity mistake: When Tanaka gives Frank the katana, Frank moves it to one side of his head, then the other. Tanaka then puts his hand on Frank's shoulder. The arc of the katana blade is pointing away from Frank and towards Tanaka. The camera then cuts to a shot behind Frank. Now the arc of the blade is pointing towards Frank. (00:16:30)
Revealing mistake: During the fight montage, the winner of the first match wins by kicking his opponent in the face. His foot never makes contact.
Answer: In the Kumite contact with the referee is apparently not illegal.
BaconIsMyBFF