This is one of the 3 swords used by Roronoa Zoro, Meito; Shusui (formerly belonged to Ryuma). After the time-skip Shusui appears to be his "go-to" sword, as it tends to be his choice when he uses Ittouryuu. He often wields Shusui with his right hand, the Sandai Kitetsu with his left, and the Wado Ichimonji in his mouth.

Shusui is one of the 21 O Wazamono grade swords and was once wielded by the legendary samurai Ryuma. It is considered the national treasure of the Wano Country. After his death, the katana was buried with Ryuma, until his grave was robbed by Moriah's crew. Ryuma appeared as a zombie on Thriller Bark, who had been given Brook's shadow. After his defeat, Ryuma bequeathed the sword to Roronoa Zoro and said he was satisfied with Zoro as the sword's master. The sword then replaced Zoro's Yubashiri which was destroyed at Enies Lobb.

Shusui's blade is black with a distinct red hamon and its tsuba hand-guard has flower-like edges, hence it is a "Black Sword". Its red Hamon (hardening line) is Kanemoto style, having the appearance of a saw or sharp teeth. It has no accessories on the hilt, being wrapped with black silk. Kashira, tsuba and kojiri end cap are golden, and the sheath is black.