Tokyo police raided the Society for Preservation of Japanese Art Swords and three other locations Wednesday on suspicion of illegally possessing some 400 unregistered samurai swords, police said.

The society voluntarily submitted the swords, excluding severely damaged ones, after finding 592 mostly rusty swords without registration cards in February and March 2009. The society, under control of the Cultural Affairs Agency, was created in 1948 to preserve Japanese swords as cultural properties after Allied Occupation forces confiscated swords following the end of World War II. It appraises swords, gives guidance on traditional sword-making and runs a sword museum.

Under the Sword and Firearm Control Law, owners are required to have their swords registered as art objects at prefectural boards of education.