Hatsukokoro Hayabusa SG2 Migaki Petty 120mm

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.

Petty knife lengths vary by maker: KAI's guide defines a petty (ペティナイフ) as a small knife with a narrow blade measuring 150 mm or under. Its table gives 90 to 150 mm, and it describes the shape as a smaller gyuto with a pointed tip.

We list petty knives from 70 mm to 165 mm, including lengths above the limit used in KAI's guide.

SG2 (Super Gold 2, which Takefu writes as SPG2) is Takefu Special Steel's own blade steel, made by powder metallurgy. Takefu says it meets all four of what it calls the major requirements for a blade: high hardness, high toughness, good wear resistance and excellent corrosion resistance.

Takefu gives its hardness as HRC 62 or more and does not publish its composition. As of 18 October 2026, 291 of the knives we list have SG2 in their title.

Neither is objectively better, it just depends on whether you value stainless convenience or a laser-sharp carbon edge. Go with SG2 if you want a knife that holds a screaming edge without any babysitting. Choose AS if you are chasing the thinnest possible edge and don't mind wiping the blade down after every use.

SG2 is a powdered stainless steel from Takefu, rated at 62 HRC or more. It is tough and resists corrosion, which is why I reach for it when working with acidic foods. Aogami Super is high carbon, and Proterial gives it a hardening hardness of over 60 HRC. It sharpens to a hair-whittling edge that lasts slightly longer than SG2, but it will rust if you neglect it.

We can't confirm that from a steelmaker. SG2 (Super Gold 2, which Takefu writes as SPG2) is Takefu Special Steel's own blade steel, made by powder metallurgy. Takefu does not publish its composition and gives its hardness as HRC 62 or more.

As of 18 October 2026, we found no steelmaker page for a steel called R2. Some knives on our shelf are listed as SG2/R2: six as of 18 October 2026, from Kurosaki, Shiro Kamo and Yoshimi Kato.

Hatsukokoro (初心) is a brand, not a forge. H&K, a company founded in 2013 and based in Amagasaki, Hyogo, created it in 2019.

H&K names the producer for some lines, for example Shinkiro by Takahiro Nihei in Fukushima, Ginyou by Yoshihiro Yauji in Echizen and Kurosagi by Motokyuichi Hamono in Nagasaki, and keeps others confidential. Some knives we stock carry the maker in the title, such as Hatsukokoro x Yoshikane SKD Nashiji.

The name comes from the Japanese proverb 初心忘るべからず, which means don't forget your original intention. The company read it gently as hatsukokoro rather than shoshin.

H&K created the brand in 2019, six years after the company was founded, and chose the name for its knife line.