Hand grenades, arming troops for centuries, took a variety of unusual forms in the hands of soldiers throughout the course of World War II. The Japanese military fielded two hand thrown grenades- one designed to punch through tank armor and the other a last ditch weapon of the Japanese homeland.
With the steady degradation of the Japanese munition manufacturing base by U.S. bombing, manufacturers turned to increasingly novel and unusual designs/construction methods especially in the Type 3 and Type 4 grenades.
The Type 3 grenade was designed to defeat Allied tanks with a tear drop-like shape charge mounted on a wooden standoff head.
The hand thrown Type 3 grenade was rather odd appearing because the outside of the body was a bag of either silk or hemp twine. The twine also created a tail-like skirt that trailed behind the grenade to help stabilize its flight toward the target.
As the Japanese people prepared for an expected invasion, lack of resources meant mass-production could not
meet war time needs and in a last ditch effort potters were pressed into service to create the body of the Type 4 anti-personal grenade.
Carried with a lanyard, the simple round terra-cotta or porcelain pot was filled with explosive. Like the most primitive explosive device, the Type 4 was ignited by a friction fuse plug and scratch block. A rubber cap is removed and the friction plug struck against the scratch block, setting a five second delay fuse, giving time to hurl the pottery grenade at invading forces.