Mahjong Kong: Types, Rules & Bonus Draws

A Mahjong kong is a declared group of 4 identical tiles. In Chinese and riichi-style rules, it fills 1 set position and normally requires a replacement draw so the hand can still reach a complete shape.

Mahjong kong at a glance

Mahjong Kong: Types, Rules & Bonus Draws: Type, How it forms, Common alternative name

Type	How it forms	Common alternative name
Concealed kong	4 self-drawn identical tiles	concealed quad, ankan
Called kong	Claim a discard with 3 concealed matches	melded quad, daiminkan
Promoted kong	Add a self-drawn tile to an exposed pung	added quad, shouminkan

“Kong,” “quad,” “kan,” and “gang” can describe the same 4-of-a-kind structure in different languages and rules documents.

Why a kong needs special procedure

A regular winning hand has 4 set positions and 1 pair. A chow or pung uses 3 physical tiles, but a kong uses 4 while still counting as only 1 set.

Without compensation, declaring a kong would leave the hand 1 tile short. Traditional rules solve that problem with a replacement tile from a designated part of the wall. The kong is not complete as a table action until its declaration, display, replacement, and any required indicator step are handled.

The exact wall area differs. Riichi draws replacement tiles from the dead wall. MCR uses the end of the wall defined by its procedure. Follow the table’s rulebook instead of reaching for any convenient loose tile.

Concealed kong

A concealed kong uses 4 tiles you obtained without calling another player’s discard. Declare it during a legal turn, show or arrange the tiles in the ruleset’s concealed-quad display, then take the replacement tile.

“Concealed” does not mean keeping the kong secret in your hand after declaration. The table must be able to verify that a kong exists and adjust the wall or indicators correctly. Display conventions often turn the outer tiles face down while leaving enough information to distinguish the group.

In riichi, a concealed kong usually preserves the hand’s closed status. A player who has declared riichi may add one only under strict conditions that preserve the hand structure and wait under the current code.

Called kong

A called kong forms when you hold 3 identical concealed tiles and claim the newest matching discard. The group becomes exposed.

The call interrupts normal turn order, subject to claim priority. After displaying all 4 tiles, draw the replacement and continue according to the variant. Do not discard before taking the required replacement tile.

Calling reveals substantial information: opponents now know the exact identity of 4 unavailable copies and can narrow the remaining shapes in your hand.

Promoted kong

A promoted kong starts as an exposed pung. If you later draw the fourth identical tile, you may declare it and add it to that group.

This creates a special risk window. Some rules let another player win on the added tile, an action called robbing the kong or chankan. If that claim succeeds, the kong and replacement draw do not complete in the ordinary way.

Under WRC Rules 2025, robbing a quad is treated as a ron win. The same code says Thirteen Orphans cannot rob a concealed quad. Other riichi organizations and regional Chinese tables may use different exceptions.

Standard declaration sequence

Use the sequence in your chosen rules. A common framework is:

1. Obtain the fourth matching tile legally.
2. Announce the kong before ending the turn.
3. Display it as concealed, called, or promoted.
4. Allow any rules-defined robbing window.
5. Draw the replacement tile from the correct location.
6. Reveal or advance any required bonus indicator.
7. Declare a win if the replacement completes the hand; otherwise discard.

Riichi adds a new kan-dora indicator after a completed kong. MCR and Hong Kong systems do not copy that dora procedure merely because they also use replacement draws.

Winning after a kong

A replacement tile can complete the hand. Several systems recognize a special scoring event for winning on that draw, often translated as win after a kong or after a quad.

The event is not automatic value in every variant. Confirm whether it is a named pattern, how it combines with other patterns, and who pays. Likewise, a win on the final discarded or robbed tile follows the local scoring code.

Should you declare the kong?

A kong can offer points, bonuses, and a new draw, but declaration changes information and risk.

Before declaring, ask:

• Does the kong improve this hand’s value under the current rules?
• Does exposing it break a concealed-hand requirement?
• Could the fourth tile serve as a safer pair or flexible triplet tile?
• In riichi, will the new dora indicator help opponents more than you?
• Is the promoted tile dangerous enough to be robbed?
• Does the replacement draw reduce the live wall at a critical moment?

Four matching tiles do not force a declaration. You can often keep them concealed and use 3 as a pung while discarding or pairing the fourth, subject to hand shape.

American Mah Jongg uses “kong” differently

On an American card, a kong is a printed group of 4 identical tiles. Eligible jokers may substitute within the group. A discard can be called to expose the grouping when the card line permits it.

American play does not treat that exposure as a traditional quad declaration. There is no replacement draw, dead-wall tile, kan-dora indicator, or robbed-kong window. Learn the joker rules and read the exact annual-card line.

Common mistakes

• Counting a kong as 2 sets because it has 4 tiles.
• Forgetting the replacement draw.
• Taking the replacement from the wrong end or wall section.
• Hiding a declared concealed kong so opponents cannot verify it.
• Adding a tile to an exposed pung without allowing the rules-defined win window.
• Assuming every set of 4 identical tiles must be declared.
• Applying Chinese kong procedure to an American card grouping.

References

• WRC Rules 2025 define called, promoted, and concealed quads, replacement tiles, robbing rules, and kan-dora procedure.
• The Mahjong Competition Rules define kong calls and MCR replacement-draw procedure.