Hiramekarei

Hiramekarei is a double handed broad sword wielded by Ganju Mushinoiki, formerly wielded by Chōjūrō. A power house weapon, Hiramekarei has two holes in it that allow the augmentation of chakra. This allows the wielder to craft weapon like apparitions around the blade. Since it came into Ganju's possession, he has learned to utilize it a little differently then Chōjūrō.

Origins
How Hiramekarei came into Ganju's possession is quite interesting. Years after the original Seven Shinobi Swordsman, only Chōjūrō was alive from them. The six other blades, destroyed or locked away during unknown battles and wars disappeared from history and faded. It was Hiramekarei, the flounder-like blade was last to survive through the Great Wars and battles Kirigakure faced. On a mission, Chōjūrō came to battle Ganju Mushinoiki. Chōjūrō was tasked with the assassination of Kidan Mushinoiki and the famed phrased "Mushinoiki will be famed. We are strong" was spoken by Ganju to Chōjūrō. It was in this battle that Ganju defeated and killed Chōjūrō, and claimed his blade as a trophy.

Ability
Its signature ability has shown to become a medium of the wielders chakra, allowing the wielder to form a large chakra-made weapon around the base blade. Through Ganju's training, he learned to use this ability to create a few abilities some of which are quite potent.