Indicating in 42 is the practice of playing a domino in a manner to provide information about the dominoes in your (bid-winning partner’s) hand so your partner can lead into your hand allowing you to take the lead (and they can hopefully safely get rid of some offs). Indicating typically occurs on the FIRST opportunity to play a domino when you don’t have to follow suit (aka when void), and by the team that wins the bid.

There are several conventions commonly used in 42 circles,  the most common being Straight indication and Reverse indication.

Let’s play an example hand in several indication scenarios for illustration.

Example: Your partner wins the bid, calls 4s as trump and leads out the 4:4. Everyone plays a 4.The next lead is the 4:6, the next highest 4. You have no 4s to play and can now play any domino you like. You have left the 6:5, 6:3, 3:3, 2:2, 3:1, 2:1.

Straight Indication

Straight indication is the practice of playing a domino – as an off – where the high end is the same suit of a double in your hand; this indicates that your partner can lead that suit to get into your hand. Typically, you should indicate your highest double and go down from there. Use straight indication so your partner:

  1. has the greatest chance to get into your hand (since as doubles decrease numerically, so do the number of dominoes available to lead into yours) and
  2. can eliminate doubles greater than the one indicated.

Example (continuing from above): You should choose between the 3:1 and the 2:1 to indicate a double in your hand. However, the best choice is the 3:1 because of the higher odds your partner may have one in that suit (3:2, 3:0 vs. 2:0).

Doubles Indication

Doubles indication is the practice of playing a double to indicate you have the next highest domino in that suit. This is another form of straight indication, however you’re spending a winner (a double) to inform your partner of the suit to lead. Typically used when you don’t have a lower one in the same suit.

Example (continuing from above): Instead of playing the 3:1 to indicate 3:3, you choose to play the 3:3 to indicate you have the 3:6 in your hand (which you do in our example). Now if a 3 is led, you can take it with your 3:6.

Reverse Indication

Reverse indication is where both ends of the domino indicate doubles you don’t have. This does not provide your partner with a specific suit they can lead to get into your hand, but it provides ample knowledge to make the best decision on what to play next.

Example (continuing from above): Instead of playing the 3:1 to indicate the 3:3 or the 3:3 to indicate the 3:6, you play your 6:5. You’ve told your partner you don’t have either the 5:5 or the 6:6, and coupled with your partner going in 4s, now your partner knows they can only hit the potential doubles of 3:3, 2:2, or 1:1. If your partner’s offs can lead into any of those doubles, the choices become that much more finite.