1. 1Tandem Mahjong rules override custom. American mahjong has many table traditions. When a Tenpai Tandem Mahjong rule differs, use the Tandem Mahjong rule in this book.
2. 2The terms East and West wear many hats. The East seat is the starting player. An East hand is a hand built from the purple East side of the card, while a West hand is built from the orange West side of the card. East hands are always built on the East side of the Tenpai Tandem Rack, and West hands on the West side. Any exposures must be placed on the corresponding side. In Tandem play, both an East hand and a West hand are built on the Tenpai Tandem Rack.
3. 3The card is exact. A winning hand must match one line from the corresponding Tenpai Tandem Card side in tile identity, quantity, group size, suit relationship, and every written restriction.

• 152 American Mahjong tiles: 108 numbered tiles, 16 winds, 12 dragons, 8 flowers, and 8 jokers. Set aside spare blanks or extra tiles.
• The 2026 Tenpai Tandem card. Your completed hands will match the lines on here.
• Racks: one single rack per Classic player, one Tandem Rack per Tandem player. Two ordinary racks placed side by side may substitute for one Tandem Rack.
• Tandem Pushers: one per Tandem Rack, used to move an active wall into reach.
• Two dice

Attain exactly 14 tiles that match one line on the card. The line is not a suggestion: every number, letter, repeated group, suit relationship, and written instruction must be satisfied.

"Identical" means the same suit and number, the same wind, the same dragon, or, because Flowers are interchangeable, any Flowers in a Flower group.

Dots, Bams, and Craks are the only numbered suits. A requirement of 1 suit, 2 suits, or 3 suits tells you exactly how many different numbered suits the line must use. Winds, Flowers, and Jokers do not count toward that total.

When a D is printed in a card color, it normally means the Dragon matching the numbered suit assigned to that color. A black D follows the printed restrictions, for example any dragon or opposite dragon.

• In Word Play, D means a Red or Green Dragon, never Soap. Soap may only be used for O.
• When a line says opposite dragon, use the Dragon matching the third, otherwise-unused numbered suit.

• A Joker may replace a missing tile in a Pung, Kong, Quint, or Sextet of identical tiles.
• A Joker may also appear in an eligible Flower group of three or more, because all Flowers are interchangeable.
• A Joker may not fill a Single, Pair, NEWS grouping, Word Play letter, Run, or other grouping of non-identical tiles.
• In By the Numbers, use Jokers only in single-suit groupings of three or more identical tiles.
• A discarded Joker is dead. It can never be called.

In a Duel game, the opponent may claim only the most recent discard. Say "Call" or "Mahjong" before the next player closes the opportunity to claim it by racking a drawn tile.

• Call a discard to complete and expose a Pung, Kong, Quint, or Sextet, or to complete your entire hand for Mahjong.
• Do not call a discard to complete a Single, Pair, NEWS, year, word, multi-suit equation, or Run, unless that tile completes the 14-tile hand for Mahjong.
• Place the called tile with the concealed tiles needed to complete the meld on the exposure ledge. The called tile must remain in that meld, which is locked to the side on which it is placed.
• After making the exposure, discard one tile to end the turn.

• Drawing a tile that completes a grouping on your card does not allow you to expose it. Keep the completed grouping concealed.
• An exposure may be made only by calling the latest discard to complete an eligible grouping. A tile drawn from the wall that completes a group may be revealed only when the player declares Mahjong.

A hand built from a Tandem Mahjong line may use exposures when permitted or may remain entirely concealed.

A mistaken exposure may be corrected before the player discards or begins a Joker exchange. The called tile must remain in a valid Pung, Kong, Quint, or Sextet. Once either action begins, the correction window closes. If the exposure remains invalid, the affected hand becomes dead. Resolve it under Invalid exposure in Duel play in Section 5.

Duel play: East opens the round

The East seat begins with one extra tile. East does not draw on the opening turn; East starts by discarding. After that, both players alternate the normal draw-or-call, then discard sequence.

Duel play order: draw first, discard last

1. 1Draw one tile from the open end of the wall, or claim the latest discard for a valid exposure or Mahjong.
2. 2Add and arrange. In Tandem play, concealed tiles may move between your East and West hand sides at any time; exposed tiles may not.
3. 3Exchange Jokers, if desired. After drawing or making a valid call, replace a Joker in any unfrozen exposed meld with the exact natural tile. You may exchange from your own rack or your opponent's rack, and may make more than one exchange.
4. 4Declare Tandem Mahjong, East Mahjong, or West Mahjong, if desired. Reveal the completed hand or hands. If the round has not ended, continue to the next step.
5. 5Discard one tile face up and clearly name it. The opponent's turn begins.

Solitaire play order: discard, then draw

Classic Solitaire begins with 14 tiles and Tandem Solitaire with 28. To keep that full working count, a solitaire cycle is reversed: discard one, then draw one. After the draw, declare Mahjong if complete; otherwise begin the next cycle by discarding.

A valid Mahjong contains exactly 14 tiles and matches one card line in every respect. Reveal the completed hand on the same side of the rack as the card side containing its line.

A standard wall is 19 stacks long and 2 tiles high: 38 tiles. A full Tandem Square uses four standard walls, for all 152 active tiles. Draw one tile at a time from the open end, taking the top tile before the bottom tile of each stack. There is no separate dead wall or reserve.

Designating East for the first round in Duel styles

Before the first round of a Duel match, each player rolls both dice. The player with the higher total takes the East seat, and the other player takes the West seat. Reroll any tie. Once the seats are set, East rolls both dice again to break the Tandem Square. After each round, the players exchange seats.

A clear way to deal in Duel styles

• Classic Duel: from the break, East takes 4 tiles, then West takes 4. Repeat until both have 12. East then takes 2 more; West takes 1 more.
• Tandem Duel: East and West alternate 4-tile packets until each has 24. East then takes 4 more; West takes 3 more.

1. 1East rolls both dice and adds the total.
2. 2From East's seat, begin at the right-hand end of East's Player Wall and count that many stacks toward the left.
3. 3Break after the counted stack. The next stack in the same direction becomes the first stack dealt or drawn.
4. 4Continue in that direction around the Tandem Square. When one wall ends, move to the adjacent wall without reversing direction.

In Solitaire styles, breaking the wall is not required.

A Tandem Rack holds two separate hands at once. One half is the WEST hand side and the other is the EAST hand side. Concealed tiles may move freely between rack sides, but exposed melds must be placed on the ledge of their corresponding half.

Place two standard racks side by side. The left one will be WEST and the right one will be EAST. Keep melds on the ledge of the rack that corresponds to the side of the line. All movement and commitment rules are the same as with a Tenpai Tandem Rack.

A declared East or West hand occupies exactly 14 tiles and becomes fixed on its side of the rack. Those tiles, including any Jokers, are no longer available for movement or Joker exchange. The other 14 tiles remain active. Discard one to return the active hand to 13 tiles; on later turns, draw to 14 and discard back to 13 until you reach your next Mahjong.

The four walls touch only at their inner corners. Do not overlap adjacent walls or press their sides together.

1. 1Shuffle all 152 active tiles face down.
2. 2Place the two Tandem Racks opposite one another with their exposure ledges facing inward.
3. 3Connect the two halves of each Tandem Pusher. Position the Tandem Pushers between the racks on each side to form the outer frame of the Tandem Square. The pushers are held magnetically against the exposure edge of the two Tandem Racks.
4. 4Inside the frame, build one wall along each Tandem Rack and each Tandem Pusher. Each wall contains 19 stacks that are two tiles high.
5. 5The four walls will touch at the inner corners to form a closed square. The empty area in the center is used for discards.

As a Side Wall becomes the active draw wall, use the Tandem Pusher to move it forward without disturbing the stacks.

• Tandem Solitaire setup: build two adjacent walls in an L, touching only at one inner corner. Begin at the right-hand end of the horizontal wall and draw continuously through the corner into the second wall. For Double Down (see Section 4), build one standard wall, draw the opening 28 tiles from the remaining tiles, and set the rest aside.
• Classic Solitaire setup: build one standard 38-tile wall and set all other tiles aside. For Double Up (see Section 4), build one standard wall and set the rest aside. Draw the opening 14 tiles from the wall.

You do not have to announce or commit to a specific line when play begins. While your tiles remain concealed, you may change your target line, suit assignments, and tile arrangement at any time.

An exposed meld is permanently committed to its EAST or WEST card side, but it does not require you to commit to a specific line. Your completed 14-tile hand must ultimately match one complete line from the corresponding side of the card, but you can pivot among lines on the same side that match what you have already exposed.

Card colors do not represent fixed suits (Dots, Bams, or Craks). Instead, they establish relative suit relationships within that specific line. You assign suits as you build your hand.

Example. If a line reads 11 22 in Green and 33 in Pink, the 1 Pair and 2 Pair must belong to the same suit (for example Dots), and the 3 Pair must belong to a different suit (for example Bams). You cannot assign both colors to the same suit.

A requirement of 1, 2, or 3 suits is exact. Flowers, Winds, and White Dragon used as O or 0 do not add to the suit count.

• Word Play (West side). Spell the printed phrase with one tile per letter. Spaces and punctuation use no tiles. I = 1 of any suit, O = Soap, D = Red or Green Dragon, N = North, E = East, W = West, S = South.
• By the Numbers (East side). Collect the digits that make the printed equation. Mathematical symbols use no tiles. The equations may be made using any numbers together, regardless of suit. Jokers are only allowed when the like-number group of three or more is built using one suit.
• Present Tense (West side) and Flashback (East side). Build the exact year or number shown. Every 0 is Soap. When O or 0 appears, it is suit-neutral and does not count for suit counting.

The simplest learning style: one 14-tile hand against a 38-tile wall.

Setup

• Shuffle the tiles and build one standard wall of 19 two-tile-high stacks. Set all other tiles aside.
• Draw 14 tiles from the wall and place them on the rack.
• Work toward any line on either the West or East side. The Charleston is optional.

Play

• Discard one tile face up to a dead discard area, then draw one tile from the open end of the wall.
• Discard and draw until it is possible to declare East Mahjong or West Mahjong.
• Discards are dead and cannot be picked up.

Win

Complete one card line before the wall runs out.

A two-player race. The WEST seat uses only the orange West side of the card; the EAST seat uses only the purple East side.

Setup

• Build a full Tandem Square. Adjacent walls touch only at their inner corners.
• East rolls the dice, breaks the East Player Wall, and deals East 14 / West 13.
• The Charleston is optional.

Play

• East opens by discarding. Players then alternate: draw or call, arrange, exchange Jokers if desired, and discard.
• West may complete any West-side line. East may complete any East-side line.
• Any line may use exposures when permitted or be played entirely concealed. Calls and Joker exchanges follow standard play.

Win

• The first player to complete their side's line declares West Mahjong or East Mahjong and wins the round.
• If the Tandem Square runs out before a winner declares Mahjong, the round is a Square Game with no winner.

Build one WEST hand and one EAST hand at the same time. Both must be declared together as a Tandem Mahjong.

Setup

• Build two adjacent standard walls in an L shape with their inner corners touching. Set the remaining tiles aside.
• Draw 28 tiles from the two-wall path and place them across the West and East sides of the Tandem Rack in any arrangement.
• Skip the Charleston.

Play

• Discard one tile, then draw one from the wall.
• All concealed tiles form one flexible pool. Move them freely between the West and East hand sides as the two target lines develop.
• Discards are dead; there are no calls or exposures.

Win

Declare Tandem Mahjong with a 14-tile hand matching any line on the West side and a 14-tile hand matching any line on the East side before the wall runs out.

The signature Tenpai Tandem game. Each player builds one WEST hand and one EAST hand from a shared Tandem Square.

Setup

• Build the full Tandem Square with four corner-touching walls. West and East sit behind their respective Player Walls.
• East rolls 2 dice, breaks the East Player Wall, and deals East 28 / West 27.
• Skip the Charleston. Players may distribute concealed tiles between the two sides of their racks however they wish.

Play

• East opens by discarding one tile from either hand side of the rack.
• Players then alternate: draw or call, arrange their tiles, make any Joker exchanges, declare Mahjong if desired, and discard if play continues.
• While concealed, tiles may move freely between hand sides. Discards may come from either side.
• When you call a discard, place the completed meld on the corresponding East or West side of the ledge immediately. An exposed meld may never move to the other side.
• Use the corresponding Tandem Pusher to bring each wall into reach as it becomes active.

1. 1On your turn, draw a tile or make a valid call. You now have 28 total tiles.
2. 2If one 14-tile hand exactly matches a card line, announce East Mahjong or West Mahjong.
3. 3Expose all 14 tiles on the corresponding half of the Tandem Rack. Identify the card line and verify it.
4. 4Score it as your first single Mahjong. The entire hand is now frozen; its Jokers cannot be exchanged and none of its tiles may move.
5. 5Discard one tile from the remaining 14. You will continue subsequent turns with 13 active tiles, drawing to 14 and discarding back to 13.

Completing the second hand

When the active hand reaches 14 tiles and matches a line, declare the corresponding East Mahjong or West Mahjong, which must be made from a line on the opposite side from your first Mahjong. Score it as your second single Mahjong, reveal it, and end the round.

Holding out for Tandem Mahjong

You are never required to declare East or West Mahjong. You may keep one completed hand concealed while working to complete the other. If both 14-tile hands are complete after the same draw or call, reveal them together and declare Tandem Mahjong. The round ends immediately; no discard is made.

Every line has a point value at the far right of the card. Classic Duel scores that printed value. In Tandem play, the value can be multiplied according to how the two hands are completed.

The order of separate Mahjongs can change the total because the second line is doubled. A simultaneous Tandem Mahjong always triples both line values.

Classic Solitaire scores the printed value of the completed line, and Double Up scores 2 × the combined value of both lines. Tandem Solitaire scores 3 × the combined value of the two lines, and Double Down scores 4 × the combined value.

A Square Game occurs when the wall runs out before the winning Mahjong is declared. In Classic and Solitaire styles, no one wins. In Tandem Duel, each player keeps the points for any East or West Mahjongs exposed on their rack. Concealed or incomplete hands score nothing.

Last available tile. The final tile may be drawn and used according to standard play. If Mahjong is not declared, the player's resulting discard remains live for Mahjong only. If it is not called for Mahjong, the round ends as a Square Game.

1. 1Count exactly 14 tiles per declared hand.
2. 2Locate the chosen line or lines on the correct East or West side.
3. 3Check group sizes, exact or consecutive numbers, suit count, color relationships, Dragon rules, and any Joker restriction.
4. 4In Duel play, only after both players agree that the hand is valid should the wall be disturbed or the next round begin.

Classic Duel

If a declared East or West Mahjong fails verification, it scores no points and that hand becomes dead. The round is over.

Tandem Duel

• If a declared East or West Mahjong fails verification, it scores no points and that hand becomes dead. Leave its 14 tiles exposed and frozen. They may not move, be used for Joker exchanges, or be declared again.
• If the invalid declaration was the player's first Mahjong, the round continues. If the opposite hand is still active, the player continues normal play with that hand and may score it as a single Mahjong. The player cannot win the round because both hands can no longer be completed.
• If the invalid declaration was the player's second Mahjong, the game ends and points are tallied for any valid exposed Mahjongs.
• If the invalid declaration was part of the player's Tandem Mahjong, the game ends and no Tandem score is awarded. Score the valid hand as a first single Mahjong, and declare the invalid hand dead. If neither hand is valid, no points are scored.
• Any single Mahjong points awarded before an invalid declaration remain scored.

Solitaire styles

An invalid Mahjong declaration scores nothing. Return the tiles to the rack and continue if tiles remain available.

For a scored match, agree on a fixed number of rounds or points to reach, alternate the East seat after every round, and add each player's points. Highest total wins. This match format is optional; the card's scoring system works equally well round by round.

• Allowed only in Pungs, Kongs, Quints, and Sextets of identical tiles, including identical Winds, Dragons, and groups of 3 or more Flowers, which are interchangeable.
• Never in Singles, Pairs, NEWS, Runs, or groups of different numbers or suits.
• Discarded Jokers are dead.
• After drawing or calling a tile, exchange the exact natural tile for a Joker in any unfrozen exposed meld.
• Declaring an East Mahjong or West Mahjong during Tandem Duel freezes all 14 tiles and Jokers in the exposed hand.

• Every player builds one West hand and one East hand, regardless of seat.
• Concealed tiles may cross between hand sides, but an exposure commits to one side permanently.
• On their turn, a player draws or calls one tile to build either hand, and discards one tile.
• A normal Tandem Duel win requires one player to declare both an East Mahjong and a West Mahjong, either on separate turns or together on the same turn.
• Tandem Mahjong requires both complete hands to be revealed during the same turn.