Naohito Myojin Cobalt Special COSP Santoku 180mm

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First, a few words on Cobalt Special steel (COSP):

For its first few years of release, COSP was shrouded in mystery. Only in recent years was the formulation published by Takefu. Based on its composition, we can see that COSP has elements that place it somewhere in between SG2 and VG10. According to Takefu: "COSP is ... achieved through a special remelting method that results in a uniform composition and fine dispersion of carbides". We can ascertain from this that COSP is probably a powdered metallurgy or sprayform steel which allows it to achieve a finer microstructure. From our analysis, we expect this steel to perform better than VG10 in terms of edge retention, but with an increased toughness, allowing the knife to take on a thinner and more aggressive grind without the risk of chipping. We also expect extremely high peak sharpness as Cobalt plays a key role in refining grain structure by resisting grain growth during heat treatment.

Basically, COSP is: extremely fine grained, extremely easy to sharpen, extremely stainless, has good toughness and with a decent edge retention exceeding that of VG10 but slightly below SG2.

Now onto the knife:

Hand-finished by rising sharpening talent Naohito Myojin in the Kochi Prefecture, this gyuto features Cobalt Special steel (COSP) - an advanced stainless steel developed by Takefu Special Steel. With performance comparable to SG2, it offers exceptional edge retention, outstanding corrosion resistance, and ease of sharpening, thanks to a finely tuned microstructure made possible through the addition of Cobalt and a special remelting method.

Composed of 1.1% carbon and 16% chromium, with additions of tungsten, molybdenum, vanadium, and cobalt, this steel forms a stable matrix of fine carbides. Cobalt in particular plays a key role: it increases hardness and refines grain structure by resisting grain growth during heat treatment.

The blade features a partial kasumi finish over a polished migaki base, giving it a sleek, sophisticated look. Myojin’s signature grind - thin, convex bevels with a small secondary edge - allows for low-friction slicing and excellent food release.

As the sharpener behind renowned lines like Tetsujin and Konosuke Fujiyama, Myojin brings a deep level of precision and polish to every knife. With its refined geometry, elegant finish, and modern stainless performance, Myojin's Cobalt Special series is a compelling alternative to his higher-priced SG2 blades.

Blade Type: Santoku
Core: Cobalt Special (COSP) Powdered Stainless Steel
Cladding: Stainless Steel Cladding
Handle: Ebony Octagonal Handle with White Buffalo Horn Ferrule
Spine Thickness at Heel: 2.1mm
Blade Height at Heel: 47mm
HRC: 60-61
Weight: 129g
Blade Length: 168mm
Overall Length: 312mm