Type 4 Incendiary Rocket (RoSa)

The Roketto Yon-shiki Shō-san-dan (ロケット四式焼霰弾, "type 4 incendiary rocket"), sometimes just RoSa-dan (ロサ弾, "incendiary rocket", abbreviation of the name) were anti-aircraft rockets used by the Imperial Japanese Navy during the World War II, combining incendiary shrapnel elements. The rocket is designated with the English borrowing "rocketto", but stays more commonly classified as a "shell" (弾, "dan"), borrowing partially the technology used by the Type 3 anti-aircraft shell "San Shiki".

Source: Wikipedia — Type 4 Incendiary Rocket (RoSa) (CC BY-SA 4.0)