Chankan

Chankan

Chankan (槍槓, ちゃんかん) is a rare 1-han yaku earned by calling ron when another player adds a fourth tile to an existing open pon, converting it to a kan (shouminkan). You “rob” their kan by claiming the fourth tile as your winning tile before they complete the kan declaration. The name translates to “robbing a kan.”

Chankan in detail

How It Works

Chankan occurs in a specific scenario:

1. An opponent has an open pon (three identical tiles) exposed
2. They draw the fourth matching tile
3. They declare shouminkan (adding the fourth tile to upgrade pon → kan)
4. That fourth tile is your winning tile
5. You call “ron!” and rob their kan

The fourth tile is treated as a discard for ron purposes, you win as if they had discarded it normally. The kan declaration is interrupted and never completes.

Types of Kan

Chankan only applies to shouminkan (added kan):

• Cannot rob ankan: Concealed kans (four tiles from closed hand) cannot be robbed
• Cannot rob minkan: Initial open kans (calling a fourth tile) cannot be robbed
• Can rob shouminkan: Only when adding a fourth to an existing pon

This limitation exists because ankan tiles never leave the player’s hand, and minkan’s fourth tile was already treated as a discard when called. Only shouminkan exposes a “new” tile that can be claimed.

Exception: Kokushi Musou

One special case exists: a hand tenpai for kokushi musou may, under many common rules, rob even a concealed ankan for the terminal or honor tile it needs, the only hand permitted to. (Robbing a daiminkan is never relevant: its fourth tile was a discard, so you could simply have ronned it directly.) Not every ruleset allows the kokushi exception, so confirm the table rule.

Strategic Implications

Shouminkan Risk: Players must carefully consider whether to declare shouminkan. If opponents are in tenpai and the fourth tile might complete their hand, declaring shouminkan becomes dangerous. Many players avoid shouminkan in tense late-game situations.

Chankan Awareness: When you hold an open pon and draw the fourth tile, ask yourself: “Could this be someone’s winning tile?” If yes, you might discard a different tile instead of risking chankan.

Rare Occurrence: Chankan is one of the rarest yaku because it requires:

• You being in tenpai waiting for a specific tile
• An opponent having a pon of that exact tile
• That opponent drawing the fourth tile
• That opponent declaring shouminkan instead of discarding

All these conditions rarely align, making chankan a memorable event when it occurs.

Walking through Chankan

You’re in tenpai waiting for 7-dots to complete your hand. An opponent has an exposed pon of 7-7-7 dots from an earlier call. On their turn, they draw the fourth 7-dots and declare “kan!” to add it to their pon (shouminkan). Before they complete the kan, you immediately call “ron!”, the fourth 7-dots is your winning tile. You reveal your hand and score chankan (1 han) plus any other yaku. The opponent’s kan never completes, and they pay for dealing into your hand despite not technically discarding.