A high-carbon steel from the Yasugi works in Shimane Prefecture, named for the blue paper the mill wraps its billets in. Chromium and tungsten let it hold an edge far longer than ordinary carbon steel — hardened to 61–63 HRC, it takes a finer edge than a Western knife can and keeps it through real work. It's the core of all four of our Japanese kitchen knives.

Thinner, harder, and lighter. A Japanese blade parts food rather than wedging through it, so tomatoes give up without a fight and the cut lands where you aimed it. The steel is hardened well beyond what a German knife will tolerate, the profile is flatter, and the handle balances forward toward the blade. Once you've used one, the difference isn't subtle.

Hand wash, dry the blade, and give it a drop of oil now and then. That's most of it. Over time the steel darkens into a grey patina — earned, not applied — and the walnut handle deepens with it. Cared for that way, one of these knives will outlast you.

Yes, and you should. Blue Paper Steel No. 2 is one of the easier premium steels to sharpen — it takes a keen edge on a water stone with very little effort, which is a large part of why it’s the steel most chefs name first. Avoid pull-through sharpeners and electric grinders; both are too aggressive for hardened steel this thin and will do damage that takes real work to undo.

Bone, frozen food, and anything on a hard surface. At 61–63 HRC these edges are ground thinner than a Western blade would tolerate, and that thinness is the entire point — but it also means the edge chips where a softer blade would simply roll or dull. Use a wooden or soft-plastic board; glass, stone, and ceramic will destroy an edge in a single use. The nakiri deserves particular mention: it looks like a cleaver and works nothing like one. Keep it to vegetables.