After a Kan

What is After a Kan in Japanese Mahjong?

After a Kan is a one-han yaku in Japanese Riichi Mahjong awarded for winning off the supplementary draw you receive immediately after declaring a kan. After a Kan is a unique one-han yaku awarded when you declare a kong and immediately draw your winning tile from the dead wall. It applies to both open and closed hands, making it a versatile but often situational yaku. While it adds an element of excitement and potential reward, players must weigh the advantage of an extra draw and possible point boost against the risk of revealing a kan and granting extra dora to everyone at the table.

How to Achieve After a Kan？

Kong Declaration：During play, you may form a kong (a set of four identical tiles) from either:

• A concealed kong using tiles in your own hand, OR
• An open kong by claiming a fourth tile that matches your existing triplet, OR
• A “declared” kong when you upgrade an already opened pung into a kong by adding the fourth identical tile.

Supplementary Draw (Dead Wall)

• After declaring any kong, you immediately draw one additional tile from the dead wall.
• If that tile completes your winning hand, you qualify for After a Kan.

One-Han Yaku: After a Kan is always worth one han, regardless of whether your hand is open or closed. This one han is added on top of other yaku you may have.

What is the Strategy and Risk of After a Kan?

Winning from the Dead Wall: The key point is that you must complete your hand specifically on the tile drawn from the dead wall following your kong declaration. If your hand completes by another player’s discard or by your next normal draw, it does not count as After a Kan.

Open vs. Closed Hands: After a Kan does not require a closed hand. An open hand can still earn After a Kan if the winning tile comes from the supplementary draw. However, additional yaku like Riichi or Fully Concealed Hands do require a fully concealed hand, so combining those with After a Kan typically necessitates a concealed kong or a closed hand before the kong.

Multiple Kongs: If you declare multiple kongs in a single hand, you get a supplementary draw each time. Each draw has the potential to yield a After a Kan if it completes your hand at that exact moment.

Risk vs. Reward: Declaring a kong can be risky because it gives extra dora flips to everyone, potentially increasing opponents’ hand values as well. However, the opportunity for a After a Kan can be a nice bonus, turning a normal win into something more valuable (especially when combined with other yaku or dora).

Dead Wall Knowledge: The dead wall is set aside at the start of each hand and typically not in direct circulation. Some advanced players track discards and draws to estimate the likelihood of valuable tiles in the dead wall, though it’s largely unpredictable.

Timing Your Kong: You might hold off on declaring a kong until you are already one tile away from winning. This maximizes the chance that the supplementary draw will be your winning tile.

Potential for High-Value Hands: If you’re also in Riichi with a concealed hand, drawing a After a Kan could stack with other hidden dora (ura dora) or even Ippatsu, depending on the timing. This can lead to surprisingly large point gains.