A petty knife is a small Japanese utility knife, typically with a blade between 120mm and 180mm, designed for precision tasks like peeling, trimming, and slicing fruits and vegetables. You need one when your main chef’s knife feels too large for detail work, think deveining shrimp, cutting garnishes, or any in-hand peeling where a bigger blade gets in the way. Its slightly longer and slimmer profile than a Western paring knife gives you more control for intricate cuts without sacrificing the nimble feel you want for small jobs. If you regularly find yourself reaching for a smaller blade for finishing work, a petty fills that gap cleanly.

A petty is not a replacement for a gyuto or santoku. It lacks the blade length and belly for efficient chopping, rocking, or breaking down larger proteins. If your work is mostly bulk prep, like dicing onions or slicing roasts, a petty will feel slow and underpowered. It also won’t handle heavy tasks like splitting bones or prying, so treat it as a precision tool, not an all-rounder.

The petty’s role in a Japanese kitchen is as the smaller counterpart to the gyuto, built for tasks where a full-size blade is clumsy. At Knives and Stones, the petty category covers a range of steels including VG10, White#2, Swedish Steel, VG5, SG2, and MV, from makers like Sakai Takayuki, Masamoto Sohonten, Ryusen, Nigara, Hatsukokoro, and Sentan. Most are double-beveled, and the blade length runs from 120mm to 180mm, which is what gives it that balance of reach and precision. For more on how this fits into your knife kit, see the Knives and Stones Education Centre.

Shirogami 1 (White 1) has a higher carbon content than Shirogami 2 (White 2), roughly 1.3% vs 1.1%, making it the purer carbon steel and the one some craftsmen still regard as the best, though in practice the two have become harder to distinguish as modern metallurgy has made both quite pure.

White 2 (Shirogami #2) has about 1.1% carbon and a hardness range of 60-64 HRC; White 1 sits around 1.3% carbon. That 0.2% difference is the core spec gap. More carbon generally means you can push hardness higher and hold a keener edge, but it also makes the steel more brittle and less forgiving. White 2 trades a bit of that potential peak sharpness for slightly better toughness and ease of sharpening.

Shirogami 1 carries a certain prestige. Sukenari's Nobuo Hanaki once told me directly that they only use White 1 for their mizu-honyaki because it is the pure form of carbon steel, it carries that halo. Among traditional smiths, White 1 is still spoken of as the benchmark. That said, in recent years the improvement in metallurgical manufacturing has narrowed the real-world gap. The rumor is that both grades are now so pure that separating them in practice is no longer straightforward. I've also heard that Hitachi has stopped producing White 1, though I can't confirm that.