Masamoto Sohonten Hongasumi White 2 Sujihiki 270mm KS4327

Between 210 and 270 mm, depending on where it will work. One Japanese maker lists 210 to 240 mm, double-bevel, for home use and 240 to 270 mm, single- or double-bevel, for professional kitchens.

Another, in Sakai, recommends 240 mm at home, with the size of your board in mind, and 270 mm for professional use.

A sujihiki is a long, double-bevel knife for dividing larger pieces of meat into their parts, and its length lets it slice sashimi too; a yanagiba is the sashimi knife.

The Sakai cutlery association describes the yanagiba (柳刃包丁) edge as so acute that it cannot be used on bone or other hard things, so choose the sujihiki for meat and the yanagiba if sashimi is the main job.

Shirogami 1 (White 1) has a higher carbon content than Shirogami 2 (White 2), roughly 1.3% vs 1.1%.

White 2 (Shirogami #2) has about 1.1% carbon and, per Proterial, a hardening hardness of over 60 HRC; White 1 sits around 1.3% carbon. That 0.2% difference is the core spec gap. More carbon generally means you can push hardness higher and hold a keener edge, but it also makes the steel more brittle and less forgiving. White 2 trades a bit of that potential peak sharpness for slightly better toughness and ease of sharpening.

Shirogami 1 carries a certain prestige. Sukenari's Nobuo Hanaki once told me directly that they only use White 1 for their mizu-honyaki because it is the pure form of carbon steel, it carries that halo. Among traditional smiths, White 1 is still spoken of as the benchmark.

They follow Masamoto's own product numbering, which has three parts: a class code set by manufacturing method and steel type, a number unique to each shape, and the first two digits of the length in millimetres, written as 18 for a 180 mm knife.

On one of the titles we list, KS0424 reads as KS for the class, 04 for the yanagiba (柳刃) shape and 24 for 240 mm.

KS and KK are two of Masamoto's class codes, which its code list sets by manufacturing method and steel type: KS is the hongasumi (本霞) class and KK is the kasumi (霞) class.

Masamoto lists white steel (玉白鋼) for both classes.

No. Masamoto Sohonten's own history page says Tsukiji Masamoto set up business independently in 1951. Its products and company organisation differ completely from the Sohonten house, and the MASAMOTO trademark is a registered trademark of Masamoto Sohonten, based in Azumabashi.

Both names carry Masamoto, so check which house made the knife: Masamoto Sohonten is the Azumabashi house in Tokyo, and Tsukiji Masamoto is a separate company.

The Masamoto Sohonten history page dates the start of the house to 1866, when the founder returned home and began making cooking knives in Osawa. It says the house was first in the Kanto region to manufacture and sell genuine tempered blade cooking knives in 1874, and it opened in present-day Azumabashi, Sumida-ku, Tokyo in 1890.

The MASAMOTO trademark, No. 20269, was registered in 1903. The history page lists six generations, from the founder Minosuke Matsuzawa to Masahiro Hirano.