The Type 21 and Type 22 rocket-bombs were rocket artillery systems used by garrison troops of the Imperial Japanese Navy during the late stages of World War II in defense of island bases in the Pacific.

Details on the Type 21/Type 22 were gathered from Japanese technical documents and analysis of a dud that was found during the war.

[2] The rocket booster was similar to the smaller Type 10 and 3, in that the rocket booster consisted of an adapter plate, propellant chamber, butt plate, tail cone, braced tail fins, and a single venturi.

[2] An adapter sleeve fits into the tail of the warhead and the forward end of the rocket motor and was riveted around the circumference joining the two.

[3] Type 21/Type 22 rocket-bombs were launched from crude V-shaped metal troughs similar to those used for the 19 cm rocket motors.