Karaten
![](/images/thumb/Dead_Wait.png/250px-Dead_Wait.png)
![](/images/thumb/Keishiki_ankan.png/250px-Keishiki_ankan.png)
![](/images/thumb/Karatenpon.png/250px-Karatenpon.png)
Karaten 「カラテン」, or empty tenpai, is a tenpai hand that cannot win because all possible winning tiles are visibly unavailable. These include tiles discarded, used as a dora indicator, in an opponent's tile call, and/or already exist in one's hand. While a tile may be unavailable if it is in an opponent's hand or in the dead wall, those would be unknown to the player.
Karaten hands are generally considered tenpai for the purpose of ryuukyoku, except if all four copies of the winning tile are in the player's own hand.
The fifth tile case
When a hand has all four copies of a tile, and is waiting on a fifth copy of a tile, it may not considered tenpai at all. Example:
If this hand could obtain a fifth 5-pin, it could win by completing a triplet and pair.
Similarly, this hand could complete a sequence if there was a fifth 3-pin, but all four are part of a kan.
This is subject to rule variation. In some platforms, hands like these still count towards tenpai.
Cases
- On Ron2, there has been an instance of a person being able to call riichi with a gutshot wait shape for a 6-pin when they have made a closed kan of 6-pin already. The hand was considered noten, but did not trigger a chombo penalty (mainly due to programming assuming no one could do something that could be viewed as faulty). The hand was not in a valid tenpai shape when it came to scoring a drawn hand, but not okay for determining if a player was legally allowed to declare riichi.
- On Tenhou, there have been reports of a hand containing 12s44466688p with a kan of 3s, scored as in tenpai.
- Likewise, the same kind of case is counted as tenpai in Mahjong Soul.