As a result, literacy increased. In 1488, the Korean Choe Bu observed during his trip to China that "even village children, ferrymen, and sailors" could read, although this applied mainly to the south while northern China remained largely illiterate. In Buddhism, great merit is thought to accrue from copying and preserving texts. The 4th-century master listed the copying of scripture as the first of ten essential religious practices. The importance of perpetuating texts is set out with special force in the longer Sukhāvatīvyūha Sūtra, which urges the devout not only to hear, learn, remember and study the text but to obtain a good copy and to preserve it. This "cult of the book" led to techniques for reproducing texts in great numbers, especially the short prayers or charms known as "dhāraṇīs". Stamps were carved for printing these prayers on clay tablets from at least the 7th century, the date of the oldest surviving examples. The Golden Age of Islam witnessed text printing, including passages from the Quran and hadith, embracing the Chinese craft of paper making, developed it and adopted it widely in the Muslim world, which led to a major increase in the production of manuscript texts. The printing technique in Egypt was adopted reproducing texts on paper strips and supplying them in various copies to meet the demand. Block printing, known as "tarsh" in Arabic, was also developed during the ninth and tenth centuries, mostly for prayers and amulets. Evidences tell that the print blocks made from non-wood materials, possibly tin, lead, or clay. Europe adopted woodblock printing from the Islamic world, at first for fabric, the method of metal block printing remained unknown in the West. Block printing later went out of use in the Muslim Timurid Renaissance. Printing with a press was practiced in Christian Europe as a method for printing on cloth, where it was common by 1300. Images printed on cloth for religious purposes could be quite large and elaborate, and when paper became relatively easily available, around 1400, the medium transferred very quickly to small woodcut religious images and playing cards printed on paper. These prints were produced in very large numbers from about 1425 onwards. Around the mid-century, "block-books", woodcut books with both text and images, usually carved in the same block, emerged as a cheaper alternative to manuscripts and books printed with movable type. These were all short heavily illustrated works, the bestsellers of the day, repeated in many different block-book versions: the Ars moriendi and the Biblia pauperum were the most common.