Shagai

The astragalus of a sheep is an irregular block of bone with four sides broad enough to land on, and on the steppe each of those four is named for an animal: horse, sheep, camel and goat. Every household that eats mutton produces them, so the material is free and universal, which is a large part of why the practice is everywhere from the Altai to Manchuria.

Cast in fours, the combination that lands is read. Four alike is the strongest result and is treated as a marked outcome; other combinations carry their own readings, and local traditions differ on the detail. The same bones support a whole family of games: flicking one bone at another across a table, shooting at a line of them, racing pieces along a track of them, sorting and matching them. Adults and children play, and the reading and the playing are not kept in separate compartments.

Sets are accumulated, kept in a pouch, dyed or polished with handling, given to children, and passed on within a family. A large old set is a genuinely valued possession, which is an unusual status for something that starts as a by-product of dinner.

Nothing is manufactured. The bones arrive from a slaughtered animal, are cleaned, and enter use, which means a household's set grows out of what it has eaten and can be replaced indefinitely at no cost.

The atlas already holds astragaloi, the ankle bones thrown for divination and games in the Greek and Roman world, and the resemblance to shagai is exact rather than approximate. The same bone, from the same part of the same kind of animal, with the same four landing faces, thrown in the same small numbers, read for answers and played with for entertainment, across both cultures.

It is tempting to make that into a transmission argument, and it does not support one. A sheep has two astragali and every pastoral society kills sheep. The bone is nearly cubical, resists rolling, lands reliably on one of four faces, and is produced in quantity at no cost. Anywhere people keep sheep and want a randomising object, this is the obvious one, and it would be surprising if it had not been found independently many times over.

What comparison can honestly do here is narrower and more useful. It can ask which faces are given which values, what the combinations are called, and how the reading is structured, because those are cultural rather than anatomical. The Mongolian naming of the faces after four herd animals is specific to a place where those four animals are the herd, and that is the level at which the object tells you something about the people using it.