During his adventures, Zoro has acquired many swords. The three he currently uses are: Wado Ichimonji, Sandai Kitetsu and Shusui.
Wado Ichimonji is a sword of great personal importance to Roronoa Zoro, and it was once Kuina’s and her family’s sword. It is also one of the 21 O Wazamono grade swords.
Shusui replaced the now destroyed Yubashiri. It 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.
Sandai Kitetsu is one of the Wazamono grade swords, a “Sharp Sword”. Like all of its predecessor Kitetsu swords, this one is said to be cursed.
After the time-skip, Shusui appears to be Zoro’s “go-to” sword as it tends to be his choice when he uses Ittoryu. He often wields Shusui with his right hand, the Sandai Kitetsu with his left, and the Wado Ichimonji in his mouth.
For one reason or another, maybe as a demonstration of his skill because he can use any sword he must at any time, Zoro has one or more of his swords destroyed, removed from his possession, or incapacitated in some way:
-Katana x2: both were destroyed by Dracule Mihawk
-Johnny’s and Yosaku’s swords returned to them after the battle
-Hana Arashi (Sogeking, handcuffed to Zoro, holding on to Yubashiri. It stopped being used when Sogeking was unlocked from Zoro)
-Yubashiri (now destroyed and replaced by Shusui) was one of the fifty Ryo Wazamono grade sword. Zoro obtained this sword for free from a sword shop owner.
-Marine cutlass x2: the first one was destroyed by Shu, and the second one was consequently left behind after the immediate battle at Enies Lobby.