The Dong-Feng 21 (DF-21; NATO reporting name CSS-5 - Dong-Feng () is a two-stage, solid-propellant, single-warhead medium-range ballistic missile (MRBM) in the Dong Feng series developed by China Changfeng Mechanics and Electronics Technology Academy. Development started in the late 1960s and was completed around 1985-86, but it was not deployed until 1991. It was developed from the submarine-launched JL-1 missile, and is China's first solid-fuel land-based missile. The U.S. Department of Defense in 2008 estimated that China had 60-80 missiles and 60 launchers.