Graeber / Wengrow 412: "Shang diviners appealed to gods through the medium of burnt offering. The process was as follows: when hosting gods or ancestors at a ritual meal, kings or their divingers put turtle shells and ox scapulae on the fire, then 'read' the cracks that broke out on their surfaces as a kind of oracular writing"
"Once an answer had been obtained, the diviner or an appointed scribe would then authorize the reading by etching an inscription on to bone or shell, and the resulting oracle would be stored for later consultation. These oracle texts are the first written inscriptions in China we actually know about."