The Mah Jongg puzzle of the day

One rack a day, the same for everyone: a Charleston pass or a discard, where one choice is clearly best and a beginner's rule of thumb misses it. Choose yours, then see its grade, the best choice and why. No account needed.

How the puzzle is made

• From the robots' games. Each day's puzzle is a moment from a game the robots played: a rack at the Charleston, or a discard in the middle of a game.
• One choice is clearly best. A moment is kept only when the best choice beats the rule of thumb (pass or discard the tiles least near a hand) by a clear margin, and still comes out ahead when both are played out 400 times on the same draws.
• Graded as the Game Review grades your own games: the hands each choice keeps within reach, their chances, and the expected points given up.
• The coach's explanation of why the best beats the tempting answer is read and approved by a person before you see it.

More on the engine, the robots and the Game Review: How it works.

With a free account

Your answers kept, and counted in how everyone chose; your days in a row; the beginner lessons, a new strategy lesson every week, unlimited games against robots that play like people, and a review of a game every day.