Mekuri-Pai refers to the tile that is turned over 5 tiles back from the far end of the wall during the set-up stage of the game. It indicates which tile is a Dora or Bonus tile. When a player completes his hand he scores extra points for each Dora that is in his hand.
The Dora is the next tile in sequence to the tile that is turned over in the wall (the Mekuri-Pai). Thus, if the Mekuri-Pai were the 3-Bamboo then the 4-Bamboo would be the Dora or Bonus tile. The player who completes his hand would be awarded a bonus point for each 4-Bamboo that his hand contains. Likewise, if the Mekuri-Pai were the 6-Coins, the Dora would be 7-Coins.
- If the Mekuri-Pai were 9-Bamboo, then the Dora would be 1-Bamboo and likewise for the Coins and Characters.
- If the Mekuri-Pai happened to be 1-Characters, the Dora would be the 9-Characters.
- If the Mekuri-Pai were a Wind then the Dora would be the next wind in sequence: Ton–Nan–Sha–Pei–Ton.
- If the Mekuri-Pai were a Dragon then the Dora would be the next dragon in sequence: Haku–Hatsu–Chun–Haku.
As play proceeds more tiles may be turned over on the wall next to the original Mekuri-Pai, in an anticlockwise direction. Each new Mekrui-Pai indicates an extra Dora so that as more Mekuri-Pai are turned over, the number of potential Dora that a hand may contain also increases.
Where two similar Mekuri-Pai are turned over, the corresponding Dora tiles are worth two points each. Where three similar Mekuri-Pai are turned over the corresponding Dora tiles are worth three points each. Likewise, if four similar tiles should be turned over the corresponding dora tiles would be worth four points each.
There are two other types of Dora:
1. The North Wind, or Pei
The North Wind, or Pei is a Dora. When you draw this tile you place it face up in the right hand corner of your side of the table and say “Dora! ” as you do so. Then draw an extra tile from the back of the wall and proceed with play by discarding a tile.
When all four Pei tiles have been played another tile is turned over on the wall as explained previously (see Mekuri-Pai).
There are some occasions when a player may choose not to treat Pei as a Dora.
1. If the player is trying to build a special hand called Kokushimuso (see Yaku…) he will need one, possibly two, Pei as part of the hand.
2. When another player has gone Riichi, or seems to be Tenpai, Pei is sometimes discarded as a “safe” tile. However, beware that nobody is waiting for it to complete Kokushimuso!
3. When other players seem ready to complete, and three Pei are already in play, a defensive player who draws the fourth Pei may keep it hidden in his hand to prevent another Mekuri-hai being turned over in the wall. (Remember, when all four Pei have been exposed an extra tile is turned over on the wall to reveal extra Dora tiles.)
2. Red Fives
In most Mahjong sets the designs of two each of the 5-Coin and one of the 5-Bamboo tiles are coloured red. If players agree, these “Red Fives” can be nominated as extra Bonus tiles. They are treated as normal tiles during play, but each “Red-Five” in a completed hand is counted as an extra Bonus.