The Shisui (凪水 Calm Water) is a white-wood shirasaya, a katana without a tsuba or guard, wielded by Motoko Aoyama. Its design is typical of the swords found in the Shinmeiryu school of swordsmanship, possessing two bells tied with red string at the base of the grip.
Originally Tsuruko Aoyama’s favored sword, she passed Shisui on to her sister, Motoko, as a farewell gift before leaving to embark on missions for the school.
Motoko kept Shisui as her primary weapon, training with it and taking it with her when she moved to the Hinata-Sou. However, when Tsuruko arrived at the dormitory to bring Motoko back home, Motoko attempted to dissuade her sister by lying about being engaged to marry and, having discovered the lie, Tsuruko defeated Motoko in a duel and broke Shisui’s blade as punishment, and with it, Motoko’s spirit was also broken.
Though Motoko eventually recovered from the ordeal, having found and obtained the Hina Blade to use as her new primary weapon, it is unknown whether the Shisui was ever reforged, though a Shinmeiryu blade similar to Shisui is tucked in Motoko’s belt during the incident surrounding Kanako Urashima’s arrival to Hinata-Sou.
- Kuro Arashi: The Prequel Story (First appearance)