Kyūna shi

A razor sharp katana designed for speed, durability, and unparalleled sharpness. Crafted from a metal known as Jin'sei and mixed with diamond dust during the forging this blade has been seen to cut cleanly through blades of steel. The entire katana has diamond dust throughout; meaning even the flat of the blade can easily cut through skin and scratch a diamond. Forged in the black flames used by Kyūketsuki, this blade reflects light so brightly as to have been compared to a highly polished diamond and its durability has shown to hold the same standard. This is the sword Kyūketsuki uses most often for his Thousand Amber Blades blade-style.

Kyūna shi has been optimized for speed, the blade shaped so that drag has only a minimal effect, and precision. The speed of this blade is made to be one of the greatest strengths of the ''"Thousand Amber Blades" style, using it to hit the opponent with waves of fast and precise strikes with many blades.

With the exception of the durability and sharpness of the blade, due to diamonds, and the speed of the blade, due to the special forging process, there is nothing that sets Kyūna shi apart from any other katana. Meaning that this blade possesses no inherent special ability or any poison coatings to give the wielder a special edge in combat.