Nakagawa Blue 1 Damascus Kamagata Usuba 210mm

The kamagata usuba (鎌型薄刃) is the Kansai type, with a pointed tip; the ordinary square usuba is the Kanto type, and both are single-bevel.

A knife maker's guide says the pointed tip can also do decorative cuts (飾り切り), angled slicing (そぎ切り) and fine work (細工), while in the Kanto style that work goes to a separate mukimono knife (むきもの細工包丁). Check the current range for square and kamagata usuba, including left-handed kamagata options when available.

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, which makes both, describes each the same way: an alloy steel with tungsten and chromium added to improve heat-treatment properties and wear resistance, hardening to over 60 HRC.

Its figures give Blue 1 (青紙1号) more carbon and tungsten, 1.25 to 1.35% carbon and 1.50 to 2.00% tungsten against Blue 2's 1.05 to 1.15% and 1.00 to 1.50%, with chromium of 0.30 to 0.50% against 0.20 to 0.50%.

Yes, Satoshi Nakagawa forges those lines for the Hatsukokoro brand, and our product titles name them Hatsukokoro by Nakagawa and Hatsukokoro x Nakagawa. He works from his own company in Sakai, Nakagawa Uchihamono.

He trained for sixteen years under Kenichi Shiraki as his only disciple and successor. He forges White 3 to White 1, Blue 2 to Blue 1, stainless Ginsan, VG10 and honyaki, so the steel in each line title is part of your choice.

Pick by how much care you want to give. Ginsan is stainless, while Blue 1 and Blue 2 are carbon steels that need to be dried and oiled after use.

If you will dry and oil the blade after each use, a Blue 1 or Blue 2 line can suit you, and if you want the least fuss in a busy kitchen, Ginsan is the easier choice.