Gokotai (五虎退, Five Retreating Tigers) is a katana. Named after a tantô forged by Awataguchi Yoshimitsu. Owned by a Japanese envoy to the Ming Dynasty, in the Muromachi period, he was suddenly attacked by five tigers. In a state of somewhat legitimate panic, he drew his tantô and started to wave it around like a maniac. The tigers soon started to panic too and went away, as if the blade's magical powers warded them off.
Latter, the tantô was given to Meiji-Tennô, and appraised by an Hon'ami polisher, who stated the blade should be rated higher. Then, Meiji the Great laugh (!) saying he should be able to ward off up to 10 tigers with it.