section_path: History
section_name: History
paragraph_text: History
  
  Gunpowder bombs had been mentioned since the 11th century. In 1000 AD, a soldier by the name of Tang Fu (唐福) demonstrated a design of gunpowder pots (a proto-bomb which spews fire) and gunpowder caltrops, for which he was richly rewarded. In the same year, Xu Dong wrote that trebuchets used bombs that were like "flying fire", suggesting that they were incendiaries. In the military text Wujing Zongyao of 1044, bombs such as the "ten-thousand fire flying sand magic bomb", "burning heaven fierce fire unstoppable bomb", and "thunderclap bomb" (pilipao) were mentioned. However these were soft-shell bombs and did not use metal casings.
  
  Bombs made of cast iron shells packed with explosive gunpowder date to 13th century China. Explosive bombs were used in East Asia in 1221, by a Jurchen Jin army against a Chinese Song city. The term for this explosive bomb seems to have been coined the " thunder crash bomb " during a Jin dynasty (1115–1234) naval battle in 1231 against the Mongols.
  
  The History of Jin (金史) (compiled by 1345) states that in 1232, as the Mongol general Subutai (1176–1248) descended on the Jin stronghold of Kaifeng, the defenders had a " thunder crash bomb " which "consisted of gunpowder put into an iron container... then when the fuse was lit (and the projectile shot off) there was a great explosion the noise whereof was like thunder, audible for more than thirty miles, and the vegetation was scorched and blasted by the heat over an area of more than half a mou. When hit, even iron armour was quite pierced through."
  
  The Song Dynasty (960–1279) official Li Zengbo wrote in 1257 that arsenals should have several hundred thousand iron bomb shells available and that when he was in Jingzhou, about one to two thousand were produced each month for dispatch of ten to twenty thousand at a time to Xiangyang and Yingzhou. The Ming Dynasty text Huolongjing describes the use of poisonous gunpowder bombs, including the "wind-and-dust" bomb.
  
  During the Mongol invasions of Japan, the Mongols used the explosive "thunder-crash bombs" against the Japanese. Archaeological evidence of the "thunder-crash bombs" has been discovered in an underwater shipwreck off the shore of Japan by the Kyushu Okinawa Society for Underwater Archaeology. X-rays by Japanese scientists of the excavated shells confirmed that they contained gunpowder.