Oracle bones

Oracle bones are a type of artifact found in archaeological sites from the Shang Dynasty in China. The site of Anyang had over 10,000 of these objects, primarily ox shoulder blades and turtle shells carved with archaic forms of Chinese characters, used for divination between the 16th and 11th century BC. The Late Shang Dynasty Yinxu site also had an abundance of oracle bones.

Oracle bones were used to practice of a form of divination, fortune-telling, known as pyro-osteomancy. Pyro-osteomancy is when seers tell the future based on the cracks in an animal bone or turtle shell either in thei natural state or after having been burned. The cracks were then used to determine the future. The earliest pyro-osteomancy in China included the bones of sheep, deer, cattle, and pigs, in addition to turtle plastrons (shells). Pyro-osteomancy is known from prehistoric east and northeast Asia, and from North American and Eurasian ethnographic reports.

Of most interest to historians are the scratchings discovered on the surface of Shang dynasty oracle bones, which have been identified as precursors to Chinese characters. Oracle bones of the Shang dynasty were ox scapulae and plastrons only, and they had characters and holes drilled into them. Flad suggests that Shang dynasty may have incised the characters to "fix the future," such that by drilling holes and making marks before firing, the bone would crack in the "right" places.

Studies
 
A great deal of knowledge of the Shang Dynasty has been learned from the studies of the oracle bone inscriptions. Many books about the inscriptions were published. The first book by Liu E was published in 1903. A good collection of the inscriptions was published in a book called 'Jiaguwen Heji' by Guo Moruo et al. It includes 41,956 inscriptions selected from the oracle bone inscriptions found before 1973. The total 13 volumes of the book were published during 1978 and 1982. From the studies of many scholars, about 2,000 characters among the more than 4,500 different characters found on the bones have been identified. The remaining unidentified characters are mainly places, names, etc. So experts can basically read the inscriptions now. 

Source: AboutArcheology.com