At some point before gaining control of the Toyko underworld, O-Ren Ishii was given a sword made by Hattori Hanzō. O-Ren's sword was only seen being used twice. The first time was during the Yakuza bosses council meeting where O-Ren is seen decapitating Boss Tanaka for bringing up her Chinese and American heritage as a negative. The second and last time, is when she and Beatrix Kiddo fight with both of their swords. The lack of a hand guard (tsuba) or handle wrapping classifies this sword as aikuchi (匕首?) (literally "fitting mouth"). Aikuchi is a form of mounting for small Japanese swords in which the handle and the scabbard meet without a guard (tsuba) in between. Aikuchi is style of sword mounting that is popular with Japanese nobility, perhaphs signifying O-Ren's status as queen of the underworld in Japan.
Her particular sword is notable due to the sakura (cherry blossom) design on the handle (tsuka). The sakura and the cherry blossom are linked to the Japanese cultural views on the ephemeral nature of life, transience of blooming seasons, exquisite beauty, volatility, mortality, graceful acceptance of destiny and karma, nationalism, and militarism. O-Ren shows all of these traits.