Type 91 is a fragmented cast steel grenade which could also be fired as a mortar bomb.
Before throwing, the fuze had to be struck against a hard object to fire the delay of 7-8 seconds.

The base held a small propelling charge which was left unused when thrown as a handgrenade.

Height : 125mm
Diameter : 50mm
Weight : 530gram including 63gram Tolite.


Base cartridge :

Shown on the photos below and right, are the different components of the base.
The actual propelling charge is missing in these pictures.

Photos © .

the base primer :

Photo Dr. Ruby