A simple katana handed down from Isamu's father down to him through his uncle.
This katana is relatively simple in design, 2 shaku in length (23.9 in.) as most other katana are. What makes this sword unique is its own given aesthetic design and the single-use trick it has within its scabbard.
The scabbard and the hilt of the sword are made of stained yew wood, stained a deep red like crimson. Overlain are iron caps on both the scabbard and hilt which form which hold floral designs on them. The hilt of the katana itself is wrapped in black silk of a fine quality.
The guard of the katana carries on a similar design in of itself, splitting into 4 edges and holding a shape design like that of a set of butterfly wings after the Mon of the Taira clan.
Within the scabbard of the sword there is a small mixture of dust, pepper, and iron filling which upon releasing the sword would fly out to those who were in front of it. The use of this is to temporarily blind the enemy in some way, exposing them in some way so that Isamu can easily slice down on his opponent with a single, fatal blow. At least, this was the original purpose as thought by his father Ken'ichi.