Hiramekarei

Name: Hiramekarei (ヒラメカレイ)
Wielder: Chōjūrō
Debut (Manga): Chapter 454

Hiramekarei is a double-handled sword wielded by Chōjūrō. So far the Hiramekarei's abilities are unknown. However, it is apparently heavy, as Chōjūrō tires out by carrying it.

Trivia

Both hirame and karei are Japanese names for species of flounders. The flounders with their eyes on the left side of their body are called hirame (鮃, 平目, 比目魚), while those with their eyes on the right side are called karei (鰈). Coincidentally, Hiramekarei is shaped like a fish.
Hirame can also come from hirameku (閃く, "to flash," to flicker). Karei can also mean splendour (華麗).
Hiramekarei seems to strain Chōjūrō's back as he carries it around with him.
Hiramekarei is one of two swords of the Seven Swordsmen that is wrapped in bandages, the other being Kisame's Samehada.