of Military Classics, states that in 994 A.D. the city of Zitong was attacked by an army of 100,000 men who were driven back by regular war machines and fire arrows. In 1076 Vietnam's Lý dynasty used fire arrows against the Song army and razed three Chinese cities. In 1083 Song records state that the court produced 350,000 fire arrows and sent them to two garrisons. On March 1, 1126, the Song general Li Gang used a fire arrow machine known as the Thunderbolt thrower during the Jingkang Incident. By 1127 the Jin were also using fire arrows produced by captured Song artisans. In 1159 fire arrows were used by the Song navy in sinking a Jin fleet. In 1161 the general Yu Yunwen used fire arrows at the Battle of Caishi, near present-day Ma'anshan, during a Jin maritime incursion. By 1206, "gunpowder arrows" (huoyaojian) rather than just "fire arrows" (huojian) were mentioned. In 1245, a military exercise was conducted on the Qiantang River using what were probably rockets. The Mongols also made use of the fire arrow during their campaigns in Japan. Probably as a result of the Mongolian military campaigns the fire arrows later spread into the Middle East, where they were mentioned by Al Hasan Al Ramma in the late 13th century. In 1374 the kingdom of Joseon also started producing gunpowder and by 1377 was producing cannons and fire arrows, which they used against wokou pirates. Korean fire arrows were used against the Japanese during the invasion of Korea in 1592. In 1380 an order of "wasp nest" rocket arrow launchers were ordered by the Ming army and in 1400 rocket arrow launchers were recorded to have been used by Li Jinglong. In 1451 a type of mobile rocket arrow launcher known as the "Munjong Hwacha" was invented in Joseon. The Japanese version of the fire arrow was known as the bo hiya. The Japanese pirates (wokou, also known as wako or kaizoku) in the 16th century were reported to have used the bo hiya which had the appearance of a large arrow. A burning element made from incendiary waterproof rope was wrapped around the shaft and when lit the bo hiya was launched from a mortar like weapon hiya taihou or a wide bore Tanegashima matchlock arquebus. During one sea battle it was said the bo hiya were "falling like rain". Rocket invention The dating