Every hand of American Mah Jongg is a bet on one line of the card. Beginners usually pick the line they like; better players pick the line their tiles already point at, and change their mind when the table tells them to.

Pick from what you hold, not from what you want

Look down your rack and count, for each line you can see on the card, how many of its tiles you already have. The line that needs fewest new tiles is your starting bet, even if it pays less than the pretty one two rows down. A 25-point hand you finish beats a 75-point hand you do not.

A line built from groups of three is the friendliest kind: every group can take a joker.

Three things make a line easier than it looks:

  • It uses groups of three or more. Jokers can fill those. A line of pairs and singles cannot be helped by a joker at all.
  • It uses tiles you hold two of. A pair is halfway to a group, and a thrown tile can complete it.
  • It shares tiles with a second line. Then one draw improves both, and you have not committed to either yet.

When a line is dead

A line is dead when the tiles it needs can no longer be got. That happens quietly, so it is worth checking on every turn:

  • Count what is visible. Four of every number exist in each suit. If three 7 Dots are on the table and one sits in somebody's exposure, a line needing a group of 7 Dots is finished.
  • Watch the pairs. A pair or a single on the card must be real tiles. Once three of a wind are gone, a line wanting a pair of them is almost certainly dead.
  • Read the exposures. Two exposures on one rack usually name that player's line. If it is the line you are on, you are racing for the same tiles, and one of you will lose.

At the school's table, the card marks a line gone when it can no longer be finished, and the button Why is my hand dead? tells you which tiles killed it.

Count what is visible. Once three are gone and one is exposed, any line wanting that group is finished.

Changing your mind without wasting the hand

Switching lines is not a failure; hanging on to a dead one is. The trick is to switch to a line that uses what you have already collected:

  • Move along the same suit: a consecutive-run line and a like-number line often share most of a rack.
  • Move within the same section: the sections of the card are grouped because their hands rhyme.
  • Keep the pairs you have, and throw the tiles the new line has no use for, starting with singles.

If you have exposed a group, your choice is narrower: you can only finish lines that still fit what is face up on your rack. That is the real cost of calling early, and the reason to wait until the call clearly moves you toward something you can finish.

The rule of thumb

Ask on every turn: if I drew nothing useful for the next five turns, would this line still be reachable? If the answer is no, you are on a hope rather than a plan, and it is time to look at the card again.

Practise this

  • Drill: which line do these tiles make? It shows a rack and asks which hand on the card it is nearest.
  • Play a hand with full help on: the card ranks every line by how far away it is and tells you what each still needs, which is the same reasoning, done for you, until you can do it yourself.