SKD vs SG2 / R2 SKD / SG2 / SPG2（粉末ハイス）
Short answer
Both hold an edge well. SG2 (R2) is a powder-metallurgy stainless run at 63–64 HRC: very long edge life, fully stainless, but chippy and slower to sharpen. SKD is a semi-stainless tool steel: slightly less edge life, a bit tougher, can stain. Yoshikane's sought-after SKD line is the reference in Sanjo.
| SKD | SG2 / R2 | |
|---|---|---|
| Hardness (typical HRC) | 62–64 | 63–64 |
| Type | semi | stainless |
| Easy to sharpen | ●●●●● | ●●●●● |
| Edge retention | ●●●●● | ●●●●● |
| Rust resistance | ●●●●● | ●●●●● |
| Chip resistance | ●●●●● | ●●●●● |
| Mark on the blade | SKD | SG2 / SPG2 / R2 / 粉末 |
| Whetstone | 1000 → 3000 | 1000 → 3000–5000 |
Scores are relative, 1–5, for kitchen-knife use — our summary of maker data and common experience, not lab tests. Heat treatment and grind can move a knife a full point either way.
SKD SKD
Cold-work tool steel with ~12% chromium. Yoshikane's signature: stains slowly, sharpens like a carbon steel.
Who uses it: Yoshikane Hamono
Sanjo examples with prices:
No Sanjo price rows yet.
SG2 / R2 SG2 / SPG2（粉末ハイス）
Powder-metallurgy stainless. Long edge life, chips if abused. Kataoka's TAMAHAGANE and Kiryu's SPG2 line.
Who uses it: Kataoka Seisakusho, Kiryu Kogyo, Baba Hamono (Sakai), Hatsukokoro (Hyogo (brand)), Hitohira (Tokyo), Kato Yoshimi (Echizen (Takefu)), Konosuke (Sakai), Kurosaki Yu (Echizen (Takefu)), Miyabi (Seki), Nigara Hamono (Tsugaru (Aomori))
Sanjo examples with prices:
- Kataoka Seisakusho — TAMAHAGANE 響十 筋引 · ¥27,629
Care
Stains slowly rather than rusting fast, but still wipe dry after use.
Wipe dry after use. Dishwasher still not recommended — the heat and detergent dull the edge and loosen handles.