Kans (槓)

26.1 Three Types of Kan

A kan (槓) is a group of four identical tiles. There are three types of kan declarations, each with different mechanics:

Ankan (暗槓) — Closed Kan

When you hold four identical tiles in your concealed hand, you may declare ankan. The four tiles are placed face-down (traditionally two face-down, two face-up to show the tile type). Your hand remains closed—ankan does not open your hand. You draw a replacement tile from the dead wall, a new dora indicator is revealed, and you discard.

Daiminkan (大明槓) — Open Kan from Discard

When you hold three identical tiles and another player discards the fourth, you may call daiminkan. This opens your hand (if not already open). You draw from the dead wall, a new dora indicator is revealed, and you discard. Daiminkan is strategically risky because it opens your hand, reveals information, and gives all players additional dora.

Shouminkan (小明槓) — Added Kan / Kakan

When you have an existing open triplet (from a previous pon) and you draw the fourth copy, you may add it to form a kan. This is also called kakan (加槓). The added tile can be claimed by an opponent for chankan (win by robbing the kan). You draw from the dead wall and a new dora indicator is revealed.

26.2 Kan Mechanics

Rinshan Draw (嶺上牌): After every kan, the player draws one replacement tile from the dead wall. If this tile completes their hand, they win with rinshan kaihou (1 han bonus).

New Dora Indicator: After every kan, a new dora indicator is revealed on the dead wall. This creates additional dora that benefit ALL players. This is a critical strategic consideration—declaring a kan may give your opponents dora that makes their hands more valuable.

26.3 When to Declare Kan

Ankan is usually safe to declare because it doesnt open your hand and adds dora potential (including kan ura dora if you later riichi and win). However, even ankan carries risks: the new dora indicator might benefit opponents more than you.

Daiminkan is rarely advantageous. It opens your hand, reveals information, and creates new dora for everyone. Most situations where daiminkan is correct are narrow: when you need the specific tile for a kan-dependent strategy or when the rinshan draw chance is valuable.

Shouminkan should be declared cautiously. The chankan risk is small but real. The new dora might help opponents. However, if you are tenpai and the fourth tile of your pon set arrives, adding the kan gives you a free draw from the dead wall—essentially a free chance to win.

26.4 Kan Strategy — "To Kan or Not to Kan"

The strategic analysis of kan declarations is more nuanced than many beginners realize. The key considerations, as analyzed in Nagai Takanori's (長井隆典) 『現代麻雀技術論』:

Ankan (closed kan) — usually declare: You gain a replacement draw (free extra draw), new dora that you might benefit from, and potential kan ura dora if you win with riichi. Your hand stays closed. The main risk is that the new dora benefits opponents more than you — but this risk is usually worth accepting.

Shouminkan (added kan) — declare with caution: You gain the replacement draw and new dora. The risk is chankan (an opponent wins by claiming your added tile) and the new dora helping opponents. If you are already tenpai, the free draw is very valuable. If you are far from tenpai, the risk of feeding new dora to opponents may not be justified.

Daiminkan (open kan from discard) — rarely correct: This opens your hand, creates new dora for everyone, and reveals information. The only situations where daiminkan is typically justified: you are pursuing suu kantsu yakuman, or you are already tenpai in an open hand and the replacement draw gives you a free chance to win (rinshan). Most Japanese strategy sources, including content by Kobayashi Gō (小林剛), recommend avoiding daiminkan in the vast majority of situations.