These refer to the scripts carved by the ancients of the Shang Dynasty (c. 16th to 11th century B. C.) on tortoise shells and ox scapulas (shoulder blades), which are considered to be the earliest written language of China.
Their discovery was by accident.
In 1899, Wang Yirong, an official under the Qing Dynasty, fell ill. One of the medicaments prescribed by the physician was called "longgu" (dragon bones). They turned out to be fragments of tortoise shells which were found to bear strange carved-on patterns. He kept the "dragon bones" and showed them to scholars who, after careful study, came to the conclusion that the carvings were written records from 3,000 years before and were of great historical significance. Further inquiries revealed that the "dragon bones" had been unearthed at Xiaotun Village, Anyang County, Henan Province, site of the remains of the Shang Dynasty capital.
Further digs made at the site in later years brought to light a total of more than 100,000 pieces of bones and shells all carved with words. About 4,500 different characters have been counted, and 1,700 of them deciphered.
Three thousand five hundred years ago, Anyang was a marshy area teeming with tortoises, a favourite food of the local inhabitants. And the Shangs were a very superstitious people. Their rulers would resort to divination and ask the gods for revelation whenever there was a gale, downpour, thunderstorm, famine or epidemic. Before going on a war or a big hunt, they would still more want to divine the outcome.
The method of divination then was to drill a hole on the interior side of the tortoise shell and put the shell on a fire to see what cracks would appear on the obverse side. By interpreting the cracks the soothsayer predicted the outcome of an event. After each divination, the dates, the events and the results would be written down and carved on tortoise shells or bones. And the collection of these became the earliest recorded historical material in China, from which modern scholars have divined "how things were in the Shang society".
In the oracle inscriptions, one finds many pictographs in their primitive picture forms, for example, for the sun, for the cow, and so on. Together they show that a well-structured script with a complete system of written signs was already formed in that early age.
Later on, the area around Anyang became dry, and tortoises grew scarce, so people began to use bamboo strips instead for divination. From this grew the practice of asking the gods about the future by drawing bamboo sticks, as one may see today at certain temples--a practice that has its remote root in the superstition of the Shang people.