A player may claim a tile that has just been discarded by one of the other players in order to make a set of three-of-a-kind. The player claims the discarded tile by saying “Pon!” (see note 1). He then takes the tile from his opponent’s discard pile, places it face up to his right and takes the two similar tiles from his hand and adds them to it to make an “open” set of three. These tiles are considered “open” because everybody can see them.
When the player places the three tiles to his right he turns one of the tiles sideways. If he claimed a tile from the player on his right he turns the right-hand tile sideways. If he claimed a tile from the player on his left he turns the left-hand tile sideways. If he claimed a tile from the player opposite him he turns the middle tile sideways. This informs everybody where the tile came from.
The player who went Pon now completes his turn by discarding a tile from his hand. Play then passes to the player on his right.
The player has made a set of three Chun (Red Dragons) by going “Pon”.
A Kan is a set of four tiles of the same kind. Whenever a Kan is declared another tile is turned over in the wall. There are three ways of going Kan.
1. Hidden Kan (Ankan)
When a player collects four of the same kind of tile he may choose to go Kan (fig. i).
The player draws a fourth 4-Coins from the wall.
Two tiles are turned around to declare hidden Kan.
The hidden Kan as it appears to the other players.
The player now takes another tile from the back of the wall and adds it to his hand to replace the tile that was used to make Kan (fig. iv).
Finally, the player discards a tile and play proceeds to the player on his right.
The Mekuri-pai (8-Coins) has been turned over. Next the player takes a tile from the back of the wall
2. Open Kan
If a player has a three-of-a-kind set of tiles hidden in his hand (i.e. not open) he can claim the fourth tile if another player discards it by going “Kan! ” (fig. v).
The player can go Kan and claim the 6C which the player to his right has just discarded.
Hidden Kan Procedure
Open Kan Procedure
Going Kan increases the number of Mekuri-pai and creates more Dora tiles
When a player goes Kan another tile on the wall is turned over next to the other Mekuri-pai, but on the anti-clockwise side (see Bonus Tiles). This new Mekuri-pai indicates that another Dora (Bonus Tile) has been created.
When to turn over the Mekuri-pai
In the case of a hidden Kan the Mekuri-pai is turned over before the player who went Kan discards. He goes Kan, then turns over the Mekuri-pai, draws a tile from the back of the wall, and then discards a tile.
In the case of an open Kan, the Mekuri-pai is turned over after the player has discarded a tile.
The reason for this is that a hidden Kan is superior to an open Kan. The player’s reward for making a hidden Kan in a hidden hand is to have a chance to increase his Dora count should he declare Tsumo with the tile he draws from the back of the wall.
If he does not complete his hand he can still enjoy the benefit of being able to check the Mekuri-pai before he discards a tile. Remember, the Mekuri-pai tells the players which tiles are extra Dora (Bonus tiles) for the game, and this may affect the player’s decision as to which tile he will discard.
Warning No. 1: Open Hands Limit a Player’s Options
A player who has opened his hand by going Pon or Kan cannot complete his hand unless it contains either a set of Dragons, a set of active Winds, or a 2 point or higher value Yaku.
Warning No. 2: Open Hands Lower the Score of a Completed Hand
When calculating the score of a partially open hand, 1-Yaku combinations except for Dragons and active Winds (and Bonus Yaku – see Yaku Table) are eliminated from the scoring and cannot be counted. Moreover, most higher value Yaku are reduced by one point. So a 2-point Yaku is counted as just one point, a 3-point Yaku is counted as just two points and so on. BUT there some important exceptions to this rule (see note 7).
Despite the warnings given above there are several occasions when opening your hand by going Pon or Kan may be useful:
When to Go Pon
1. Going Pon to complete a set of dragons or active winds
A player who has two of the same kind of Dragons or active Winds may go Pon when another of the same kind is discarded. This is a very common form of Pon and usually the first Pon a player claims because it gives him a Yaku.
To count as a Yaku a Dragon or active Wind open Pon or Kan must be the first open Pon or open Kan that a player claims (see note 8).
2. Going Pon to develop a hand with a hidden Yaku
If a player has already built a hand which contains one or more hidden Yaku worth a total of 2 points or more he may claim an open Pon, provided he does not destroy those Yaku by so doing. He is not obliged to go Toitoi (see note 3 below). The purpose of this play is to try and bring the hand closer to completion more swiftly.
3. Going Pon to get Toitoi (“Ponning Out“)
A player may decide that his best chance of completing his hand lies in claiming any open Pon he can even though he does not have a Yaku in his hand. To successfully go out by this method a player must collect sets of 3-of-a-kind only, hidden or open. This method creates a 2 point Yaku called Toitoi.
The main reason to go Kan is to increase the number of Mekuri-pai on the wall in the hope that this will increase the Dora (Bonus tiles) count in the player’s hand. This move is best done by a player who is confident that he will complete his hand otherwise he may simply be helping another player to improve his score should that player go out first. There is little point in going Kan with an undeveloped hand.
Ideally, the player will collect 4-of-a-kind himself and declare a hidden Kan. That way he will not forfeit his right to go Riichi. If he goes Riichi he will also be able to check each tile beneath the Mekuri-hai in the wall for Dora. By making a hidden Kan the player will have two extra tiles to check in the wall, the new Mekuri-hai, and the tile beneath it.
Remember that a player who makes an open Kan (claiming the fourth tile from another player as he discards it) forfeits his right to go Riichi. This means he will not be able to check the tiles below the Mekuri-hai for extra Bonus points. He should therefore consider carefully whether the potential gains of going Kan will match the potential losses.
Another reason for a Tenpai player to go Kan is in the hope of going out on the tile that he takes from the other end of the wall to make his hand up. This finish is called Rinshyan and adds one point to the player’s final score.
Going Kan to Improve the Hand: Sankantsu (2 Yaku) or Sukantsu (Yakuman)
It may be that the player has collected two sets of Kan (hidden or open) and wishes to claim a third in order to build a 2 Yaku hand called Sankantsu. In this case he would probably seek to make a third hidden or open Kan. Likewise, a player who already three sets of Kan in his hand may seek to build a high scoring Yakuman hand called Suukantsu by claiming a fourth Kan, hidden or open.
Warning: Beware of Kan Atozuke! An open Dragon or active Wind Kan is considered Atozuke if it is preceded by a Pon or an open Kan that is not a dragon or active wind (and if his hand contains less than two hidden Yaku, no hidden 3-of-a-kind dragons or active winds). Check what was said in the section on Pon Atozuke as the same circumstances apply to Kan Atozuketoo.
Going Kan after Riichi
After having gone Riichi a player can only go Kan if he takes the tile from the wall himself and only if this Kan does not alter what he is waiting for in order to complete his hand (see note 9).
A player who has gone Riichi cannot make an open Kan by claiming a tile that another player has just discarded.