Exotic: Yoshikazu Ikeda Blue #1 Mizu-Honyaki Yanagiba 300mm / Moribashi Set #1

A yanagiba (柳刃包丁) is a sashimi knife for slicing raw fish. A knife maker's guide says a sashimi knife cuts without breaking the fibres of the flesh, and that it is longer and narrower than other knives because slicing sashimi with crisp edges needs the length.

The whole length goes through one pulling cut. The Sakai cutlery association calls the yanagiba the sashimi knife used mainly in the Kansai region.

Size a yanagiba to the fish you prepare: a knife maker's guide gives 270 to 360 mm for professional use and 240 to 270 mm for home use, with 270 mm at home if you slice larger fish.

The guide says the whole length goes through one pulling cut, so do not choose too short a knife, and at home it points to the size of your board and your work space. We list the yanagiba (柳刃) from 210 to 360 mm, some made for left-handed use.

No. The Sakai cutlery association describes the yanagiba (柳刃包丁) edge as so acute that it cannot be used on hard things such as bones.

For bones the association describes the deba (出刃包丁), whose heel is used to hit them.

An encyclopedia describes sashimi knives as thin and narrow, calling the pointed ones yanagiba and the unpointed ones takohiki. A sakimaru takohiki is the rounded-tip variant, so it has a rounded point despite its takohiki name.

A trade body, the Sakai cutlery association, calls the takohiki (たこ引き包丁) the Kanto-type sashimi knife, and the yanagiba the sashimi knife used mainly in Kansai, with an acute edge that is not for bone.

A sujihiki is a long, double-bevel knife for dividing larger pieces of meat into their parts, and its length lets it slice sashimi too; a yanagiba is the sashimi knife.

The Sakai cutlery association describes the yanagiba (柳刃包丁) edge as so acute that it cannot be used on bone or other hard things, so choose the sujihiki for meat and the yanagiba if sashimi is the main job.

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, 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. In its Japanese materials, Proterial calls its Aogami (青紙) steels high-carbon steel (高炭素鋼).

Its figures give Blue 1 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%.

Mizu honyaki (水本焼) is water-quenched honyaki, and Yoshikazu Ikeda's own page says it is one of the professional Japanese knives he mainly makes. The Ikeda honyaki we list under titles that say Mizu-Honyaki are water-quenched.

On hardening, Ikeda says on the City of Sakai film site that the fire's temperature is everything and that he judges it by the colour of the flame. Honyaki can run about 1 to 2 HRC harder than comparable non-honyaki knives, and how much varies by maker.