Motokyuuichi Kurosagi AS KU Santoku 165mm Kurouchi by Hatsukokoro Black Chacate

The gyuto came to Japan with the beef-eating culture of the Meiji era, and that is where its name comes from. Tojiro says it is used for all kinds of cooking, which is why it is also called the chef's knife.

The santoku is a household knife that combines the good points of the nakiri and the gyuto. Tojiro describes it as all-purpose, from vegetables to meat and fish, double-bevel and built on the same construction as a Western knife.

Choose a gyuto if you want more length and reach. Choose a santoku if you want a shorter all-purpose knife. Tojiro's own size figures: gyuto 150 to 210mm for household use and up to 360mm for professional use, santoku 165 to 170mm for household use.

Match the shape to your stroke. Rock chopping keeps the tip on the board and rolls the curved belly through the food, so a gyuto or a Western chef's knife suits it, and Japanese knives rock fine as long as you rock gently.

Up-and-down chopping, the Chinese style, wants a straight run of edge, so a nakiri, usuba, santoku or bunka suits it better; a curved edge chopped straight down easily leaves pieces joined. Neither shape is better; it depends on how you cut.

A Japanese dictionary explains the name of the santoku (三徳包丁) as coming from the three things it handles: meat, fish and vegetables. The same dictionary entry points from the santoku to the bunka (文化包丁), treating the two as one knife.

One Japanese knife maker guide distinguishes the two by the tip. It says that in the Showa era the bunka was made with its tip cut at an angle, and the santoku came after it by rounding that tip.

Yes, carbon steels such as Aogami (Blue) and Shirogami (White) are not stainless steels, so left wet they can spot or rust.

Care is simple once it becomes habit. Wipe the blade as you go, especially after acidic food like citrus, tomato or onion. When you finish, wash it in warm water with a little soap and dry it straight away with a towel. Do not let it air dry, leave it in the sink or the dish rack, or put it in the dishwasher. Store it dry: on a magnetic strip, in a saya or in a block in a dry spot.

If the knife will sit unused for a while, wipe on a thin layer of oil before storing. In our video James shows that mineral oil can stand in for camellia (tsubaki) oil, and he picks one labelled medical grade; we list the Kitchen Knife / Cutting Board Mineral Oil Medical Grade for this. If you find light rust, lift it with a rust eraser and a little water, then dry and oil the blade; we list the CKK and Naniwa rust erasers.

Aogami Super, also called Blue Super, is a knife steel made by Proterial. Proterial describes it as an alloy steel with tungsten, chromium and vanadium, to improve heat-treatment properties and wear resistance. Its own figures put carbon at 1.40 to 1.50%, tungsten at 2.00 to 2.50%, vanadium at 0.30 to 0.50% and chromium at 0.30 to 0.50%.

Proterial gives it a hardening hardness of 60 HRC or more. The uses it lists for the grade are high quality planes, other tipped tools, kitchen knives and sickles. Proterial's hardening note calls for quenching in water, with oil as the alternative.

With chromium well under the 10.5% the Japan Stainless Steel Association sets for stainless, it is not a stainless steel. Wipe it dry after use, do not leave it wet or in the sink, and do not leave acidic food on it.

Aogami (Blue) steels are carbon and alloy steels, not stainless, so water left sitting on the blade will spot it. Each Aogami grade lists only a little chromium, between 0.20 and 0.50% depending on the grade, and that is not enough to make the steel stainless.

Dry the blade as soon as you finish cooking and after washing, and store it somewhere dry. Lift any rust early.

Will a carbon steel knife rust? covers rust removal and everyday care.

The difference is in Proterial's own figures: Aogami Super has 1.40 to 1.50% carbon, 2.00 to 2.50% tungsten, 0.30 to 0.50% chromium and 0.30 to 0.50% vanadium, against Aogami 2 (Blue 2) at 1.05 to 1.15% carbon, 1.00 to 1.50% tungsten and 0.20 to 0.50% chromium.

Proterial describes both as alloy steels with tungsten and chromium to improve heat-treatment properties and wear resistance, and also names vanadium for Aogami Super. Both pages list hardening hardness over 60 HRC, and Proterial lists Aogami Super for high-quality planes, other tipped tools, kitchen knives and sickles.

In the Edo period, 久一 (Kyuichi) flourished as sword smiths in Hizen Shimabara. As that family line faded, in 1895 (明治28年) the first generation took over the name 本久一 at the present site in Shimabara City, Nagasaki, turning the sword-smithing skills to knives, sickles and hoes.

The workshop, 前田鍛冶工房, is run today by its fourth and fifth generations.