The bones or shells were cleaned of meat and then prepared by sawing, scraping, smoothing and even polishing to create convenient, flat surfaces.
The predominance of scapulae and later of plastrons is also thought to be related to their convenience as large, flat surfaces needing minimal preparation.
There is also speculation that only female tortoise shells were used, as these are significantly less concave.
Pits or hollows were then drilled or chiseled partway through the bone or shell in orderly series.
At least one such drill has been unearthed at Erligang, exactly matching the pits in size and shape.
The shape of these pits evolved over time and is an important indicator for dating the oracle bones within various sub-periods in the Shang dynasty.
The shape and depth also helped determine the nature of the crack that would appear.
The number of pits per bone or shell varied widely.
The bones or shells were cleaned of meat and then prepared by sawing, scraping, smoothing and even polishing to create convenient, flat surfaces. The predominance of scapulae and later of plastrons is also thought to be related to their convenience as large, flat surfaces needing minimal preparation. There is also speculation that only female tortoise shells were used, as these are significantly less concave. Pits or hollows were then drilled or chiseled partway through the bone or shell in orderly series. At least one such drill has been unearthed at Erligang, exactly matching the pits in size and shape. The shape of these pits evolved over time and is an important indicator for dating the oracle bones within various sub-periods in the Shang dynasty. The shape and depth also helped determine the nature of the crack that would appear. The number of pits per bone or shell varied widely.
Oracle bone