Sugimoto Chuka (Chinese Cleaver) #7 (4007) Mid Weight White 2, Full Size

It depends on the blade thickness. A knife maker's guide sorts the chuka cleaver (中華包丁) into three thicknesses, each suited to different foods.

The thin kind (薄刃), the lightest, is for the everyday foods a supermarket sells; the medium-thick kind (中厚刃) can also cut hard foods such as bone-in chicken and fish bones; and the thick kind (厚刃), the heaviest and meant for experienced users, suits bone-in block meat and frozen food. Check the thickness of your blade before you cut any bone.

Shirogami 1 (White 1) has more carbon than Shirogami 2 (White 2): Proterial lists 1.25 to 1.35% carbon for Shirogami 1 and 1.05 to 1.15% for Shirogami 2, with the same silicon (0.10 to 0.20%) and manganese (0.20 to 0.30%) ranges for both.

Proterial describes both as carbon steel with minimum impurities, Shirogami 1 with the highest hardness and Shirogami 2 with high hardness, and gives a hardening hardness of over 60 HRC for both. It lists Shirogami 1 for the highest quality tipped tools, planes, chisels and razors, and Shirogami 2 for high quality tipped tools, chisels, razors, sickles, axes and gravers.

White 1, White 2 and White 3 are Proterial's Shirogami 1, Shirogami 2 and Shirogami 3. Proterial lists carbon at 1.25 to 1.35% for Shirogami 1, 1.05 to 1.15% for Shirogami 2 and 0.80 to 0.90% for Shirogami 3, with the same silicon and manganese ranges for all three and no chromium listed.

Proterial describes all three as carbon steel with minimum impurities, at highest, high and middle hardness in that order, and gives a hardening hardness of over 60 HRC for each.

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.

They are Sugimoto's own production numbers, original to the company, its shop says, and its cleaver categories group them by thickness: numbers 1 and 6 thin (薄口), 2, 7 and 11 medium-thick (中厚口), 3 thick (厚口) and 22 extra-thick (極厚口).

Within that numbering system, #6 is in the thin group and #7 is in the medium-thick group.