When to Play Your Doubles

A double is worth a lot, is hard to place, and under most rule settings obliges somebody to answer it immediately. That combination makes it the most interesting domino in your hand and the most dangerous one to be caught with. The timing is nearly everything.

Why doubles get expensive

Two reasons, and they compound. A double is heavy — the 12-12 alone is twenty-four points against you, more than most players score in an entire good round. And it is hard to place, because it only fits one number, where an ordinary domino fits two.

So the domino you most want gone is also the one with the fewest chances to go. Every turn you hold it, the board fills up and your chances get fewer. Players who finish rounds with doubles in hand are usually not unlucky; they were waiting for a better moment that was never coming.

Check which doubles rules your game is using

This one matters before any of the advice below, because the doubles rules are chosen by whoever created the game and they change what a double is worth doing. They are fixed once play starts and are the same for everyone at the table, so you cannot switch them mid-game — but you can look them up in Game scores and settings.

• Must satisfy doubles during play. When it is on, a played double has to be covered before the game moves on. This is what makes a double a blocking tool.
• Must satisfy doubles to go out. When it is on, you cannot finish the round while an unanswered double is sitting on any train. It can stop a win that looked certain.
• Branching doubles. When it is on, a double opens a branch and the train forks, which creates extra places to play rather than a bottleneck.

With all of them off, a double is simply a heavy tile that fits one number, and the advice reduces to “play it as soon as you can”. Everything more interesting comes from the switches being on.

The best moment: when you can cover it yourself

If you hold the 9-9 and also a 9-4, the turn you play the double is the turn you have an answer for it. Under a must-satisfy rule you are the one obliged to answer, and you can. You have shed eighteen points and set your own next move at the same time.

This is the single most reliable double play in the game, and it is worth arranging your hand so you can see it. Keeping each double next to the tiles that match it is exactly the kind of grouping the hand divider is for.

The blocking double

With must-satisfy-during-play on, a double that nobody can cover stops the table. Play the 6-6 when the sixes are largely gone and the player after you is left drawing, then passing.

This is genuinely powerful and worth a word of caution: it is powerful against everyone, including you. The obligation to cover usually falls on the next player, but a double nobody can answer is a board nobody can move on, and you have to come back round to it too. Block when you are close to going out and can afford a stalled board. Blocking from a hand of twelve dominoes mostly costs you your own turns.

Counting helps here more than anywhere else. There are thirteen dominoes of each number in a double-12 set. If you can see most of the nines already played, the 9-9 is a much stronger block than it looks.

Saving a double to go out on

Finishing on a double is satisfying and occasionally correct, but under a must-satisfy-to-go-out rule it is a trap dressed up as a plan. You play your last domino, it is a double, nobody has covered it — and you have not gone out. The round carries on and you are holding nothing but a domino you cannot use.

There is a specific escape from that, sometimes called Blake’s Rule: if your last tile is a double and the boneyard is empty, the double can never be satisfied by anybody, so you go out anyway and the round ends. The app applies it for you.

Outside that case, plan to finish on an ordinary domino and get your doubles out earlier. A double is a bad last tile and an excellent middle-of-the-round tile.

The double blank

By pip count the 0-0 is worth nothing at all, which makes it feel harmless. Many tables play a penalty on it — often 50 points — and if yours does, it is the most dangerous domino in the set: worth more than the 12-12 and playable only on blanks, which are the rarest useful number on the board.

If the penalty is on in your game, treat the 0-0 as the first thing to get rid of, not the last. The double blank rule covers the common conventions.

A short version

• Play a double the turn you can cover it yourself. That is the best case and it is common.
• Otherwise play it early, while its number is still live on several trains.
• Block deliberately, not reflexively, and only when a stalled board suits you.
• Do not save one to go out on unless the boneyard is empty.
• If the double blank carries a penalty, it goes first.

Keep reading

• How to win at Mexican Train
• The doubles rules, in full
• Opening moves and sorting your hand
• The double blank rule