Also known as: 水禺刀, 水鑑刀
Suiguutou (水禺刀, Water Monkey Sword; Sword of Suiguu) is a Sword wielded by Nakajima Youko in Juuni Kokuki.
The sword is accompanied by the Hekisoujo (Juuni Kokuki), a miraculous gem possessing healing powers. The sword, along with its Scabbard, and the gem are sacred treasures in the kingdom of Kei.
The Suiguutou was forged by Tatsu-Ou, a previous great ruler of Kei, from a water youma and it was originally known as Suikantou (水鑑刀, Water Mirror Sword). When Tatsu realized the sword's power could bewitch the wielder, he forged a scabbard to contain its magic. Because the scabbard was made from a long-tailed monkey youma, Aozaru (Juuni Kokuki), the sword was renamed Suiguutou to reflect its new nature.
The sword and scabbard change form with each new master; the blade originally took the form of a long-handled Scimitar and eventually becomes a Long Sword for Nakajima Youko.