According to Wikipedia: "XW-41 and its predecessor HY-4 lost their intended market when the wars in middle east ended, so XW-41 was converted to the first indigenously developed air-to-surface precision strike missile. The developmental work begun in the mid-1990s when Sea Eagle Mechanical-Electrical Research Academy received support of Chinese military and the project was completed in 2002. The resulting new missile was named as YJ-63, also known as C-603. In comparison to XW-41, the original radar guidance was changed to TV guidance. The original inverted Y-configuration of tail control surfaces was changed to X-configuration. Like its predecessor, XW-41, turbojet engine was adopted instead of liquid fuel rocket engine used on HY-2."