The Wado Ichimonji is a sword of great personal importance to Roronoa Zoro, and it was once Kuina and her family's sword. It is also one of the 21 O Wazamono grade swords. Upon Kuina's death, Zoro asked for it from her father.
The sword has a pure-white hilt with a circular hand-guard. The sheath is painted white and the type of the blade is suguha or straight blade.
It is described as "magnificent" by Tashigi when it catches her eye in Loguetown.
As one of the 33 finest katana in the world (12 Saijo O Wazamono, 21 O Wazamono) Wado Ichimonji is a powerful blade when used by a competent swordsman. It is also quite durable, as shown when Dracule Mihawk's Yoru shattered two of Zoro's swords, this is the only one that did not break at all.
When used by Zoro, this sword is usually placed in his mouth for his Three Sword Style. Prior to the timeskip, when using his One Sword Style, Zoro usually used this sword. After the timeskip he seems to favor Shusui for his One Sword Style. Its toughness is further demonstrated by the fact that Zoro used it for his One Sword Style Sword Draw: Lion's Song technique against Mr. 1, cutting through his steel body.
At first, Tashigi of the Marines was hunting Zoro for this very blade since she could not accept the fact that such a famous blade was in the hands of a pirate.