The DF-3 (CSS-2) is China's first domestic developed intermediate-range ballistic missile (IRBM). After the Soviets refused to provide China with R-12 (SS-4 Sandal) missile design, China decided to develop their own IRBM in early 1960s. As with the R-12, the DF-3 used storable liquid propellants and a cluster of four engines with a total lift-off thrust of 64 tons. The development of the missile, which began in September 1958, proved more difficult than expected. Early firings of the DF-3 were from Shuangchengtzu during 1967.
The DF-3 provided the first stage for the follow-on CSS-3 (DF-4) IRBM. It also provided the first stage of China's first space launch vehicle CZ-I or Long March 1.