Song Bed-Mounted Crossbow

Timeline

1. c. 1000–1127Northern Song capital and frontier garrisons · Northern SongThe Northern Song incorporated bed-mounted crossbows into city-defense formations as prescribed by the Wujing Zongyao, setting up three-bow, four-bow, and even larger bed crossbows, spanned by foot treadle or windlass, used for volley fire in city defense and for blocking cavalry in field battles.
2. 1127–1230Southern Song temporary capital Lin'an · LiangzheAfter the Song court crossed south, bed crossbows became standard equipment in Jiangnan cities; crossbow towers were widely built in Lin'an and riverine fortresses, working in division of labor with individual crossbows such as the Shenbi crossbow to compensate for cavalry inferiority.
3. 1231–1240Xiangyang · JingxiangAfter the fall of Jin in 1234 the Mongols immediately turned south, attacking the Southern Song repeatedly from 1235 onward. Bed crossbows and ballistae were deployed in large numbers at Jianghuai fortresses, using dense volleys to slow Mongol siege engines and infantry charges, becoming the Southern Song's core long-range firepower against the Mongols.