Text and picture copied from "Japanese Infantry Weapons" cincpac cincpoa Bulletin 55-45, 15 March 1945 :

"The Type 3 Hollow Charge Conical Hand Mine is thrown by hand at a tank from a minimum safety distance of 10 yards. This leather covered weapon is shaped like a truncated cone, 3 cm in diameter at the top, and 7 cm at the bottom. The fuse is the instantaneous type which detonates regardless of the angle at which the mine strikes the tank.

Attached to the fuse is a tail composed of several pieces of hemp, which affords greater accuracy and makes the mine strike base first. At the bottom of the mine is a wooden bowl shaped base with a 50 cm (mm) hole in the middle.

The explosive is composed of 500 gms of TNT, cyclonite and tetryl".