Ishizuchi Blue Super Kurouchi Gyuto 180mm (7.1")

• Brand: Ishizuchi Knife Factory (石鎚刃物)
• Style: Gyuto (Chef Knife)
• Length: 180mm (7.1")
• Blade Steel Type: Blue Super Steel clad with Soft Iron
• Handle Material: Octagonal Walnuts
• Ferrule Material：Yellow Poplar (compressed wood)
• HRC: 64-
• Weight : 5.0 oz (141g)
• Bevel Angle Ratio: Double Bevel
• Cover : Not included

Precaution

• Tosa Hamono knives have a thicker spine compared to other Japanese knives, so regular Sayas may not fit.
• All Ishizuchi knives are Soft Iron Clad and may rust.

Each knife is meticulously finished by hand, resulting in subtle differences from one to another, a characteristic feature of Tosa’s "free forging" technique. We hope you enjoy the unique quality of each blade. This knife uses Blue Steel Super, regarded as the finest material for enhancing hardness and wear resistance in the core. The outer layer of the blade is made from Soft Carbon Steel, making it very easy to sharpen. The distal taper from the heel to the tip of the blade, combined with the solid construction, provides a satisfying weight that creates a perfect balance in the hand. However, because it’s entirely made of Carbon Steel, it’s important to thoroughly wipe and dry the blade after each use to prevent rust. While the patina that forms over time will give your knife a unique character, it can be removed with products like Sabitoru if you prefer to maintain a clean finish.

Ishizuchi knives are renowned for their authentic kuro-uchi style. Unlike black-dyed knives that use a special coating for an overall black appearance, Ishizuchi’s “Kuro-uchi” knives retain the natural oxide film formed during the quenching process. This gives them a rugged, robust look and a handcrafted feel, showcasing true craftsmanship and traditional techniques.

“Black Rust”
Black rust, or protective rust, forms an oxide film on the surface of iron, preventing further rusting and avoiding the crumbling associated with red rust.

Sharpening Tip from Ishizuchi
Ishizuchi recommends sharpening the dominant side more for kuro-uchi knives, with a 40/60 bevel angle ratio for right-handed users and a 60/40 bevel angle ratio for left-handed users. Disclaimer

In 1590, warlord Chosokabe Motochika unified Tosa, documenting 399 blacksmiths in the region. Known for its forest-rich environment, Tosa required durable, high-performance tools for forestry, leading to the establishment of specialized blacksmiths. Following this tradition, Kajihira Tomika founded the Ishizuchi Agricultural Tool Company in 1920. Over 100 years later, they continue to maintain the distinctive thick, reassuring spine of Tosa knives while achieving the sharpness expected of fine Japanese knives.

The Gyuto (lit. Cow Sword) is an adaptation of the French chef knife profile for the Japanese market. While the name cow sword would imply that this knife is meant only for meat, its versatility is the same a santoku and can be used as a general-purpose knife for any task. Many would consider a gyuto or chef's knife to be the one essential knife for any kitchen with all other knives being secondary. Compared to a German-style chef's knife, a gyuto will have a somewhat flatter profile: this profile lends itself well to push-cutting which is common for Japanese chefs, as opposed to rock-chopping. Gyuto also tends to be thinner at the edge as well as the spine than most European chef's knives and as a result, has less lateral toughness and care should be taken not to torque the blade while cutting to minimize the risk of chipping.