光輝 青鋼二號 黑打 三德刀 180mm Pau Rosa 柄

牛刀是隨著明治時代的食牛文化傳入日本的，名稱也由此而來。藤次郎表示，牛刀可用於各種料理，因此也被稱為主廚刀。

三德刀是結合了菜切刀與牛刀優點的家用刀。藤次郎將它描述為從蔬菜到肉類、魚類都能處理的萬用刀，雙面刃，結構與西式刀相同。

想要更長的刃長與作業範圍，就選牛刀；想要一把較短的萬用刀，就選三德刀。藤次郎自己的尺寸數據：家用牛刀 150 至 210mm，專業用途可達 360mm；家用三德刀 165 至 170mm。

請依照自己的刀法來搭配刀型。搖切是讓刀尖留在砧板上，用弧形的刀腹在食材裡滾動，所以牛刀或西式主廚刀適合這種切法；日式刀也一樣能搖切，只要搖得輕柔。

上下直切（中式的切法）需要一段平直的刃口，所以菜切、薄刃、三德刀或文化刀更適合；弧形的刃口直接往下切，切出來的塊狀食材容易仍然相連。兩種刀型沒有優劣之分，差別只在於你怎麼切。

一本日本辭典解釋三德刀（三徳包丁）的名稱來自它所處理的三種食材：肉、魚與蔬菜。同一條辭典條目在三德刀下標註參見文化刀（文化包丁），將兩者視為同一種刀。

一份日本刀具製造商的指南以刀尖區分兩者。它表示在昭和時代，文化刀製作時刀尖為斜切，三德刀則繼其後出現，由修圓這個刀尖而成。

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 對兩種鋼都列出 1.05 至 1.15% 的碳含量；其青鋼二號表列出 0.20 至 0.50% 的鉻和 1.00 至 1.50% 的鎢，白鋼二號表則兩者皆未列出。

Proterial 描述白鋼二號為雜質極少、硬度高的碳鋼，青鋼二號則為添加鎢和鉻以改善熱處理特性與耐磨性的合金鋼，兩者的淬火硬度都在 60 HRC 以上。兩種鋼都遠低於日本不鏽鋼協會對不鏽鋼 10.5% 的最低鉻含量標準。