XII gaming

Seen at Substack, verified by an archeology book.

These mysterious dodecahedrons were fairly common in the northern part of the Roman empire, from Britain to Germany. Theories abound but nobody is certain of their purpose.

They were about 4 inches in diameter, with 12 sides. Each side had a hole, each a different size. My first thought was some kind of feeler gage. Tools often have holes of different sizes, like this crimper in my toolbox.

Some researchers think the gadget was a size checker for military equipment like arrow shafts and pike poles. This idea doesn’t work well because only a few were found near military camps.

The 12 holes are in the right size range for coins, and Romans used base 12 for fractions. This suggests a coin checker for merchants. If the coin will exactly pass through the hole for a groat, the customer’s payment of a groat is approved. Polistra demonstrates this possibility:

The gadget could also be a gambling device, for money or for divination. A 12-sided object is basically a ball, so it would roll around on any slightly rough surface. The protruding rods would guarantee settling onto one side. Much harder to cheat with sliding motions.

If gambling for religion, the zodiac comes to mind. Divination often starts by throwing an object and noting how it falls. Some of these gadgets have odd symbols carved by the holes, perhaps old astrological signs. Some were found accompanying a body in a burial, implying a religious role.

If gambling for money, perhaps the coin sizes determine your winnings or how much you put in the pot.

With input coins: Before you throw you have to put in a coin that fits one slot. If the same slot comes up, you win the pot?

With output coins: Fill it first with coins of 12 different sizes. The biggest one would be the last to fall out?

Gambling is not in my genes, so I can’t imagine the real rules of such games.

After building a digital model, I can imagine the difficulty of casting such an object with basic blacksmithing equipment. A solid ball would be fairly easy to cast with a two-part mold. But a ball with a hollow center and holes in each side might involve casting each side on its own then brazing them together. Expensive for sure!