jiandu

Jiǎndú (简牍) are long, narrow strips of wood or bamboo, each typically holding a single column of several dozen brush-written characters. They were the main media for writing documents in China before the widespread introduction of paper during the first two centuries AD. (Silk was occasionally used, for example in the Chu Silk Manuscript, but was prohibitively expensive for most documents.)

Bamboo or wooden strips were the standard writing material during the Han dynasty and excavated examples have been found in abundance. Subsequently, the invention of paper by Cai Lun during the Han dynasty began to displace bamboo and wooden strips from mainstream uses, and by the 4th century AD bamboo had been largely abandoned as a medium for writing in China.