Angle Checker Recommended by Usui Kengo 刃物角度定規

Planes (hardwood): Edge angle (29-30 degrees), Gradient (8.5 - steep slope), Suitable wood (zelkova, oak, cherry)
Planer (general wood): Edge angle (27-29 degrees), Gradient (8-8.5), Suitable wood (cedar, cypress, pine)
Planer (soft wood): Edge angle (25 to 27 degrees), Gradient (6.5 to 7.5), Suitable wood (paulownia, Japanese cypress, Japanese Spanish mackerel)
Chisel (chisel angle): Edge angle (27 to 30 degrees)

Back blade of plane: 18 to 20 degrees
When measuring the angle of the plane, it is best to measure at the point where the back (plane) of the plane is showing.