This proverb also occurs at omicroniota 106, tau 934, tau 1005, tau 1006. For ku/bos as the ace or one spot on ancient dice see kappa 2602 and omicroniota 106. It is uncertain in what game this alternative occurs; probably a dicing game, similar to modern zanzi, where the pot continued to grow as each player throwing an ace was forced to ante an agreed sum and the first triple six took the whole pot. Perhaps triple aces forced retirement from the game.
For further discussion see tau 1006.