What is "hwacha"

n. a fire cart, a mid-16th century Korean weapon that launched a barrage of rockets or arrows at enemies using gunpowder

A hwacha or hwach'a (화차; 火車) (fire cart) was a multiple rocket launcher developed by Koreans and deployed in the defence of Korea against Japanese invasion in the 1590s. It had the ability to fire up to 200 singijeon, a type of fire arrow rocket, at one time. The hwacha consisted of a two-wheeled cart carrying a board filled with holes into which the singijeon were inserted.

Some East Asian historians believe this technological breakthrough, alongside the turtle ship in the mid-16th century, had a distinctive effect during the Imjin War. Today, hwachas appear in Korean museums, national parks, and popular culture.