How to play Jactus

Jactus is Latin and simply means throw. The Romans played dice everywhere, from taverns to legion camps, but their complete rules were never preserved. The rules below are a modern reconstruction: a playable game built on what we know about Roman dice, named throws and gaming pieces. Not historical fact, but historical atmosphere.

Jactus is played with five dice and tokens, and suits two to four players. Each player starts with five tokens (coins, chips or pebbles, very much in the Roman spirit), and everyone puts two tokens in the pot before the game begins.

On your turn you roll all five dice in one throw, and the throw settles with the pot:

• Five of a kind: you win the whole pot, and the round is over.
• Four of a kind: take two tokens from the pot.
• Three of a kind: take one token.
• Five different values (the Venus throw): take one token. The Romans considered the throw where every die differed the most beautiful of all.
• Three or more ones (the dog throw): pay one token to the pot. The dog was the Roman throw of misfortune.
• Anything else: nothing happens.

The round ends when the pot is empty, or immediately when someone rolls five of a kind. The player with the most tokens wins. If the pot empties without a winning throw, count up; ties share the victory, much as the Romans shared most other things.

The reconstruction takes adjustment well: play with a bigger pot for longer rounds, or let the Venus throw pay two tokens if you want to honour the Romans. Historically they also played with astragali, small four-sided knucklebones, where the named throws mattered even more.

More games with historical roots: Hazard and Cho-Han.

Very much so. Dice have been found across the whole empire, emperor Augustus wrote about dice games in his letters, and the saying alea iacta est (the die is cast) comes from Caesar. Sadly they never wrote down the actual rules, which is why this is a reconstruction.