Standard Blocks for Hardness（YAMAMOTO）
| Standard Blocks for Hardness | HMV | JIS B 7735 |
| UMV | JIS B 7735 | |
| HN-W | JIS B 7735 | |
| HV | JIS B 7735 | |
| HS | JIS B 7731 | |
| HL | JIS B 7731 | |
| HR C | JIS B 7730 | |
| HR A | ||
| HR30N | ||
| HR15N | ||
| HR45N | ||
| HRB W | JIS B 7730 | |
| HR30T | ||
| HR15T | ||
| HREW | JIS K 7202 | |
| HRMW | ||
| HRLW | ||
| HRRW | ||
| HRFW | ||
| HRSW | ||
| HBW | JIS B 7736 |