<P> The claim that Bi Sheng's clay types were "fragile" and "not practical for large - scale printing" and "short lived" was refuted by facts and experiments . Bao Shicheng (1775--1885) wrote that baked clay moveable type was "as hard and tough as horn"; experiments show that clay type, after being baked in an oven, becomes hard and difficult to break, such that it remains intact after being dropped from a height of two metres onto a marble floor . The length of clay movable types in China was 1 to 2 centimetres, not 2mm, thus hard as horn . </P> <P> There has been an ongoing debate regarding the success of ceramic printing technology as there have been no printed materials found with ceramic movable types . However, it is historically recorded to have been used as late as 1844 in China from the Song dynasty through the Qing dynasty . </P> <P> Bi Sheng (990--1051) also pioneered the use of wooden movable type around 1040 AD, as described by the Chinese scholar Shen Kuo (1031--1095). However, this technology was abandoned in favour of clay movable types due to the presence of wood grains and the unevenness of the wooden type after being soaked in ink . </P> <P> In 1298, Wang Zhen (王 祯 / 王 禎), a Yuan dynasty governmental official of Jingde County, Anhui Province, China, re-invented a method of making movable wooden types . He made more than 30,000 wooden movable types and printed 100 copies of Records of Jingde County (《 旌 德 縣志 》), a book of more than 60,000 Chinese characters . Soon afterwards, he summarized his invention in his book A method of making moveable wooden types for printing books . Although the wooden type was more durable under the mechanical rigors of handling, repeated printing wore the character faces down, and the types could only be replaced by carving new pieces . This system was later enhanced by pressing wooden blocks into sand and casting metal types from the depression in copper, bronze, iron or tin . This new method overcame many of the shortcomings of woodblock printing . Rather than manually carving an individual block to print a single page, movable type printing allowed for the quick assembly of a page of text . Furthermore, these new, more compact type fonts could be reused and stored . The set of wafer - like metal stamp types could be assembled to form pages, inked, and page impressions taken from rubbings on cloth or paper . In 1322, a Fenghua county officer Ma Chengde (馬 称 德) in Zhejiang, made 100,000 wooded movable types and printed the 43 - volume Daxue Yanyi (《 大學 衍 義 》). Wooden movable types were used continually in China . Even as late as 1733, a 2300 - volume Wuying Palace Collected Gems Edition (《 武英 殿 聚珍 版 叢書 》) was printed with 253,500 wooden movable types on order of the Qianlong Emperor, and completed in one year . </P>

Who developed printing using wood type around 1255