Quick answer
The National Mah Jongg League's rules include a two-player game. Both players build all four walls, East is dealt fourteen tiles and the other player thirteen, and there is no Charleston, so East opens with the first discard. The card, calling, jokers and the joker exchange all work as they do with four.
The League's rules cover three players and two as well as four, and the two-handed game is simple to set up. Here is the official version, what it changes about the game, and how two players can use it to practise out loud.
Is there an official two-player game?
Yes. The National Mah Jongg League's rules include short-handed play for three players and for two, and in both the Charleston is skipped. The card is the same card, and every hand on it can be played with two.
Two-player mahjong keeps a game going when the table is short, and it is a good practice format for reading a deal.
The setup that works
Use the full set, jokers included. Build all four walls as usual, each player building their own and the one to their right, and roll the dice for East. Deal only to the two seats, fourteen to East and thirteen to the other player. The deal passes after every hand, so East alternates and the extra tile evens out.
Play across from each other, not side by side. Discards go in the middle and stay face up, and with only one opponent, every discard you did not make came from the same player, which makes them easier to read than three opponents' discards at a full table.
The Charleston with two
Under League rules there is none. After the deal, East opens with the first discard, exactly as at a three-player table.
If you are playing two-handed to practise, a pass of three tiles across, once or twice, is a table rule worth agreeing. It keeps the decision that shapes every hand, which is what to give up. Agree it before the deal, because it is your rule and not the League's.
Calling, exposing and jokers
Calling a discard works normally. The tile is claimed before the other player draws, the set is exposed on the rack, and play continues. With one opponent you see every discard the moment it lands, so the calling window is much simpler to manage.
Jokers and the joker exchange work as they do with four. The difference is who can reach them. You are the only other player who can redeem a joker in your opponent's exposures, and they are the only one who can redeem a joker in yours. Hold naturals that could redeem one.
What changes strategically
Each player draws far more often than at a full table, since two players share a wall built for four. There is also only one opponent's discards to call from, so a direction that needs called sets gets fewer chances at them than it would with three opponents throwing.
Defence is simpler. There is one opponent, one set of exposures, and one discard pile to read, so the question of what is safe to throw has a clearer answer.
Siamese Mah Jongg is a different game
Siamese Mah Jongg is a two-player variant, not part of the League's rules. The name does not mean it comes from Thailand. Gladys Grad developed it in Florida, based on the League's American rules. In the description on Tom Sloper's mah-jongg FAQ, each player plays two racks and needs a mah jongg on both to win. You may put up one finished mah jongg while you work on the other, but any jokers in it cannot be redeemed, and the scoring differs from the League's.
So if someone suggests Siamese, agree before the deal which game you are playing. The League's two-player game in this guide is one rack each, the normal deal and no Charleston.
Practising out loud with two
Talk. At a regular game of four, discussing a hand mid-play is not done. With two, especially two who are learning, you can play open racks, say out loud what direction each deal points to, argue about what to pass, and then check.
Better still, put both deals side by side before the first discard, or after your pass if you play one, and compare which direction each one favours, what the backup is, and what should go.
Put it into practice
New to the game? Start the course at Lesson 1, Meet the Tiles. The first three lessons are free and need no account.
Already play? Have the coach read a real dealt hand for you, free. It names the direction the hand goes for, what to keep, what to pass, and the reasoning behind each call.
With two there is no Charleston to repair a weak deal, so reading the deal well is where every hand starts. Mei, our AI coach, reads a dealt hand and explains the direction, the keeps and the passes in plain English, free. For the two deals on your own table, tap them into the free hand analyzer.