Kiska

The standard issue grenade used by Japanese forces. Like the Vietcong of the Vietnam War, the Japanese would arm a Kiska in a trap, such as a mine or trip-wire bomb, and would also use them for many unorthodox, yet effective, purposes. They are known to be hard to "cook", (Hold in the hand a few extra seconds, so they explode sooner) and are dangerous, considering its fuse often varied, and their explosive powers. The grenade has no safety handle like its American counterpart. Instead, the soldier would activate the grenade by pulling the pin and giving it a sharp hit against a hard suface such as a rock or a helmet. This would overcome a creep spring and crush a thin brass cap, allowing the pin to hit the primer and initiate the delay sequence before throwing at the target.

Call of Duty: World at War
In single-player campaign mode, you can pick these up from dead Japanese soldiers. These grenades are not available in Multiplayer Split-screen nor Online matchmaking. You can find 4 Kiskas in a tunnle in "Burn Em, Out".

Trivia

 * The player model in the game does not hit the grenade before throwing it. This would make it impossible to cook prior to throwing, and would only activate as the grenade hits the ground.