On the Subject of Yahtzee

When has bomb defusal ever been a game of chance?

There are five dice in the colors of purple, yellow, blue, white and black. Start by rolling the dice. Then choose which dice to keep and which to reroll. You may only keep dice of the same value. Keep repeating this process until you get a Yahtzee.*

At each stage, the dice to keep are given by the following rules:

If you just rolled 5 dice:

Follow the first rule that applies:

  • Large straight:* keep the die with the highest value equal to a digit in the serial number; if none, keep the purple.
  • Small straight:* keep the outlier.*
  • Three of a kind or full house:* keep the white die if there are ≥ 2 lit indicators; otherwise, the black die if there are ≥ 2 unlit; otherwise, the highest value not in the three-of-a-kind.
  • Four of a kind or two pairs: keep any dice matching the number of batteries; otherwise, matching the number of battery holders; otherwise the yellow die.
  • Pair: keep the die of the color listed in the first applicable row of the following table:
    If there is a...Die color
    parallel portpurple
    PS/2 port blue
    RCA port white
    RJ port black
    otherwise yellow
  • Otherwise: you must roll all the dice again.
  • In all of the above cases, dice of the same value as a die to be kept may also be kept.

Yahtzee: All dice show the same value.

Large straight: Five consecutive values.

Small straight: Four consecutive values. The outlier is the fifth die.

Three of a kind: Three dice of equal value, but not four.

Full house: Three of a kind plus two of another kind.

These terms always refer to all of the dice, regardless of which were rolled and which were kept.

If you just rolled 4 dice:

  • Straight (small or large):* you must reroll the die you previously kept and keep a die or dice of a different value.
  • Otherwise:
    • Rerolling all dice is always allowed.
    • Keeping 1 die is only allowed if it isn’t black.
    • Keeping 2 dice is only allowed if neither is blue.
    • Keeping 3 dice is only allowed if the values of the other two both aren’t in the serial number.
    • Keeping 4 dice is only allowed if the fifth die has a bigger value.
    • Keeping a number of dice equal to the number of port plates is not allowed unless it’s 2 or less.

If you just rolled 3 dice:

  • Full house:* reroll the pair if there are any duplicate ports; otherwise, reroll the three-of-a-kind.
  • Otherwise:
    • Keeping 0, 1 or 2 dice is allowed.
    • Keeping 3 dice is only allowed if purple or white was kept during the previous roll.
    • Keeping 4 dice is only allowed if the fifth die has a smaller value.
    • Keeping any number of dice is allowed if the value of the kept dice is in the serial.

If you just rolled 2 dice:

  • Keeping 0, 1, 2 or 3 dice is allowed.
  • Keeping 4 dice is only allowed if yellow or blue was kept during the previous roll or if the fifth die is 1 away in value from the value of the kept dice.

If only 1 die is left to roll:

Keep rolling it until you achieve a Yahtzee.