is dated no earlier than 704 and preserved in a Silla Korean temple stupa built-in 751. The first printed periodical, the Kaiyuan Za Bao was made available in AD 713. However, the earliest known book printed at regular size is the Diamond Sutra made during the Tang Dynasty (618–907), a 5.18 m (17 ft) long scroll which bears the date 868 AD. Joseph Needham and Tsien Tsuen-hsuin write that the cutting and printing techniques used for the delicate calligraphy of the Diamond Sutra book are much more advanced and refined than the miniature Dharani sutra printed earlier. Movable type: The polymath scientist and official Shen Kuo (1031–1095) of the Song dynasty (960–1279) was the first to describe the process of movable type printing in his Dream Pool Essays of 1088. He attributed the innovation of reusable fired clay characters to a little-known artisan named Bi Sheng (990–1051). Bi had experimented with wooden type characters, but their use was not perfected until 1297 to 1298 with the model of the official Wang Zhen (fl. 1290–1333) of the Yuan dynasty (1271–1368), who also arranged written characters by rhyme scheme on the surface of round table compartments. It was not until 1490 with the printed works of Hua Sui (1439–1513) of the Ming dynasty (1368–1644) that the Chinese perfected metal movable type characters, namely bronze. The Qing dynasty (1644–1912) scholar Xu Zhiding of Tai'an, Shandong developed vitreous enamel movable type printing in 1718. Gunpowder Evidence of gunpowder's first use in China comes from the Tang dynasty (618–907). The earliest known recorded recipes for gunpowder were written by Zeng Gongliang, Ding Du and Yang Weide in the Wujing Zongyao, a military manuscript compiled in 1044 during the Song Dynasty (960–1279). Its gunpowder formulas describe the use of incendiary bombs launched from catapults, thrown down from defensive walls, or lowered down the wall by use of iron chains operated by a swape lever. Bombs launched from trebuchet catapults mounted on forecastles of naval ships ensured the victory of Song over Jin forces at the Battle of Caishi in 1161, while the Mongol Yuan Dynasty (1271–1368) used gunpowder bombs during their failed invasion of Japan in 1274 and 1281. During the 13th and 14th centuries, gunpowder formulas became more potent (with nitrate levels of up to 91%) and gunpowder weaponry more advanced and deadly, as evidenced in the Ming Dynasty (1368–1644) military manuscript Huolongjing compiled by