The Dong Feng 31 (translated literally as "East Wind" (Chinese:东风导弹); a.k.a. CSS-9) is a long-range, three stage, solid propellant intercontinental ballistic missile in the Dongfeng missile series developed by the People's Republic of China. It is a land-based variant of the submarine launched JL-2. It is operated by the Second Artillery Corps (SAC) which is estimated to have under 15 DF-31 missiles and under 15 DF-31A missiles in inventory.[2]