Explosive bombs were used in East Asia in 1221, by a Jurchen Jin army against a Chinese Song city. Bombs built using bamboo tubes appear in the 11th century. Bombs made of cast iron shells packed with explosive gunpowder date to 13th century China. The term was coined for this bomb (i. e. "thunder-crash bomb") during a Jin dynasty (1115–1234) naval battle of 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.