The Spherical Knob Cutter is known in Japan as Kobu Kiri Hasami. These cutters are designed for removing trunk knobs and roots. The head is shaped like a ball, hence the name 'Spherical'. They produce a hollow circular cut that heals quickly and with a minimum of scarring.
The cutting edges of the Spherical Knob Cutters are rounded as compared to the straight blades of Standard Concave Cutters. The results are spherical cuts which are round and hollow and heal with the most aesthetic and least visible wounds.