Wado Ichimonji in One Piece

Wado Ichimonji, a Meito sword, was crafted by swordsmith Shimotsuki Kozaburo in Wano Country. Kozaburo took the sword with him when he left Wano and stored it in the Isshin Dojo's warehouse. The sword was rarely used in combat, as the dojo primarily used wooden swords for training. During a challenge between Roronoa Zoro and Koushirou's daughter Kuina, Kuina borrowed Wado Ichimonji.

After Kuina's passing, the sword came into Koushirou's possession. Zoro, determined to become the world's strongest swordsman, requested the sword from Koushirou, who passed Wado Ichimonji to him.

In the Loguetown Arc, Zoro, left with Wado Ichimonji after two swords were broken in a battle with Dracule Mihawk, refused to sell the sword despite an attempt by Ipponmatsu to buy it at a high price. Tashigi recognized the sword as one of the 21 legendary swords.

Later in Wano Country Arc, while training with Enma, Zoro learned more about Wado Ichimonji's origins from Tenguyama Hitetsu, who suggested it might have influenced Kozuki Hiyori's decision to bequeath Enma to Zoro.

Wado Ichimonji is a traditional Katana with a pure-white handle and a circular handguard. The sheath is also white, and the blade has a straight-line pattern. The hilt has a gray diamond-shaped pattern, a simple kashira at the end, and a golden crossguard.

The blade has a beautiful contrast of deep black and shining white, curving slightly towards the sharp tip. The sheath is completely white with a modest end.

Wado Ichimonji, created by the legendary Wano swordsmith Shimotsuki Kozaburo, is classified as one of the 21 Great Grade Swords. It ranks among the world's most powerful swords, second only to Enma.

Zoro highly values Wado Ichimonji, refusing to part with it. He often places it in his mouth during his Three Sword Style. Despite not being imbued with Haki, the sword is exceptionally durable. It withstood a strike from Dracule Mihawk's Yoru, a Supreme Grade Sword, shattered battleships, and cut a giant iceberg.

Post-timeskip, Zoro's enhanced strength, and skills, coupled with Busoshoku Haki, amplify Wado Ichimonji's power and defense. It can cut down formidable foes like Pica and even wounded Kaido when strengthened with Haoshoku Haki and Busoshoku Haki.

Both Wado Ichimonji and Enma, forged by the same person, allowed Zoro to adapt quickly to using Enma during his training period.

In SBS Volume 92, Oda drew Zoro's swords as humans. Wado Ichimonji looked like a man with a unibrow, a big nose and lips, and dark hair in a topknot. It looked a lot like Shimotsuki Kozaburo, the sword's maker.