Kouki Blue2 Kurouchi Bunka 150mm

The bunka knife (文化包丁) takes its name from bunka, culture. A Sakai knife maker ties the name to Japan's modernisation, when Western culture and Japanese tradition merged, and says it stands for that new era and for the knife's wide range of uses.

The same maker says that as diets broadened to meat, fish and vegetables, an all-purpose knife was wanted, and the bunka took features from both Japanese and Western knives.

The tip. One Japanese knife maker describes the bunka (文化包丁, kengata) as combining the good points of the gyuto and the nakiri with the tip cut at an angle, and the santoku as coming after it, by rounding that tip.

Both are all-purpose knives for the home; santoku (三徳) means three virtues, for the three foods it cuts: meat, fish and vegetables.

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.

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. In its Japanese materials, Proterial calls its Aogami (青紙) steels high-carbon steel (高炭素鋼). Neither steel is close to the JSSA's 10.5% minimum for stainless.