Hatsukokoro x Myojin Shirasagi Blue 2 Kurouchi Honesuki Boning Knife 150mm

A honesuki (骨スキ) strips meat from the bone, the job a boning knife does elsewhere.

One Japanese knife maker describes the traditional honesuki as a shape unique to Japan, made with Japanese knife techniques and ground single-bevel (片刃), so it can also be used to prepare fish.

Yes, carbon steels such as Aogami (Blue) and Shirogami (White) react with food, moisture, and acids, so left wet they can spot or rust. With normal use they develop a grey, blue and brown patina, and that patina is expected on a carbon knife rather than damage.

Aogami has only a little chromium, far below what a stainless steel needs, so water left sitting on the blade will spot it. A patina is a stable oxide layer that slows rust down; orange or red specks are rust.

Care is simple once it becomes habit:

• Wipe the blade as you go, especially after onion, citrus or tomato.
• When you finish, wash it in warm water with a little soap and dry it straight away with a towel. Don't let it air dry or leave it in the sink or the dish rack, and never put it in the dishwasher.
• Store it dry: on a magnetic strip, in a saya or in a block in a dry spot.
• If it's going to sit unused for a while, wipe on a thin film of food-safe mineral oil before storing it.

If you do find rust, lift light orange spots with a rust eraser and a little water, then dry and oil the blade. We stock the CKK and Naniwa rust erasers, and the Koyo Sunlite Polishing Paste (Blue for Steel) lifts light surface rust or refreshes a finish. Rust on the edge itself comes off the next time you sharpen. Deep pitting needs a professional sharpener. Avoid steel wool and harsh scouring on a polished or kurouchi finish, because they scratch it.

On a stainless-clad knife only the thin line of carbon steel along the edge can rust; the cladding stays clean. A carbon-clad or honyaki blade can rust over its whole face and needs the same care all over.

Carbon steel rewards this small amount of attention with a keener edge and easier sharpening than most stainless.

Proterial lists 1.05 to 1.15% carbon for both steels; its Blue 2 table lists 0.20 to 0.50% chromium and 1.00 to 1.50% tungsten, while its White 2 table lists neither.

Proterial describes White 2 as a carbon steel with minimum impurities and high hardness, and Blue 2 as an alloy steel with tungsten and chromium to improve heat-treatment properties and wear resistance, with a hardening hardness of over 60 HRC for both. Neither steel is close to the JSSA's 10.5% minimum for stainless.

A hamaguri-ba edge, written 蛤刃, is a convex edge shape, and it is the shape the workshop 明神利器製作所 sharpens its knives to. Kochi City's craft page records that Myojin Riki learned it over several years of training in Fukui.

The same page says the workshop also takes sharpening-only orders from outside Kochi.

Yes. Kochi City's craft page for his workshop 明神利器製作所 says the work runs from forging through finishing in one continuous process, 鍛造から仕上げまで一貫して行う.

That page lists the workshop in Susaki, Kochi.