[Lonesome in Massachussets]

History channel did a show on swords. They claimed that almost all the Samurai swords were sent to the U.S. after the War because the Japanese officers wouldn't retain them after they had been disgraced by defeat, so they became War trophies for lucky U.S. veterans.

[Eric in the Ozarks]

A bunch of these swords did come back with GIs but the first round of collections were stored at YED (Yokohama Engineering Depot) at Sagamihara and some at Camp Zama.
My dad knew of a guy who got the job of disposing of the swords in the sea. He picked off the gold dragons and other decorations before tossing them into the drink.