New Reference: Hitachi/Proterial Yasuki Steel Family

ScissorPedia has published comprehensive documentation of the Hitachi Metals (now Proterial Ltd., following the 2023 rebrand) Yasuki Works steel family. These are the “paper steels” — named for the colored paper wrapping used to identify grades at the Yasuki mill in Shimane Prefecture. Understanding this family helps when a maker names one of these steels.

The Silver Steels (銀紙 / Ginkami)

The stainless members of the family, and the most relevant for modern scissors:

Silver Steel #1 / GIN1 (銀紙1号) — HRC 58-59. The less common of the two stainless grades. Adequate corrosion resistance with moderate hardness. Used in some mid-range scissors but largely overshadowed by its sibling.

Silver Steel #3 / GIN3 (銀紙3号) — HRC 59-61. The workhorse of Japanese professional scissors in the mid-to-upper range. GIN3 offers a practical balance: enough hardness for excellent edge retention, sufficient chromium for genuine stainless behavior, and good machinability that allows manufacturers to achieve precise blade geometry without exotic tooling. Thousands of professional scissors in active daily use are made from GIN3.

The White Paper Steels (白紙 / Shirogami)

Non-stainless carbon steels prized in traditional Japanese toolmaking:

White Paper Steel #1 / Shirogami 1 (白紙1号): HRC 60 or over (Proterial minimum). Extremely hard, extremely pure carbon steel. Capable of astonishing edge acuity but demanding in maintenance, and it will rust without diligent care. Used in premium traditional scissors where the stylist accepts the maintenance burden.

White Paper Steel #2 / Shirogami 2 (白紙2号): Proterial publishes a hardening hardness of HRC 60 or over for its standard heat-treatment context. Slightly lower carbon, slightly more forgiving. The more common choice for scissors applications among the white steels.

The Blue Paper Steels (青紙 / Aogami)

White steel enhanced with tungsten and chromium additions:

Blue Paper Steel #2 / Aogami 2 (青紙2号): Proterial publishes a hardening hardness of HRC 60 or over for its standard heat-treatment context. Proterial describes the tungsten addition as intended to improve wear resistance over the white steels. Still non-stainless, still demands attentive care. No test here compares finished scissors, so this page states no edge-life comparison.

Blue Paper Super / Aogami Super: Proterial publishes a hardening hardness of HRC 60 or over for its standard heat-treatment context. The ultimate expression of traditional Japanese carbon steel for cutting tools. Maximum hardness, maximum edge retention, maximum maintenance requirements. Used in the most premium traditional scissors and by craftspeople who view daily blade care as part of professional discipline.

Also Documented: ATS-55

ATS-55 (HRC 58-60) is Hitachi’s budget alternative to the well-known ATS-34. Lower molybdenum content reduces cost while maintaining acceptable performance for mid-range scissors. It appears in many scissors that do not specify their steel — a useful identification clue when a manufacturer is vague about materials.

Background

These steels come from a mill with a long blade-steel history. The Yasuki Works has produced steel for blades since 1899, and the grading system — color-coded paper wrappings at the mill — predates modern metallurgical marketing by decades. When a manufacturer specifies “Aogami Super” or “Shirogami 1,” they are invoking a specific, verifiable product with documented properties, not a marketing term.

The full reference articles are available in the Steel Types section of ScissorPedia’s reference library.