Pung

A pung (also spelled pong, and called a koutsu in Japanese) is a meld of three identical tiles, such as 5p-5p-5p or three East winds. Along with the chow, the pung is one of the two basic three-tile building blocks of a standard four-melds-plus-a-pair winning hand. Because the three tiles must be exact copies, a pung can be formed from any tile in the game: number tiles, winds, or dragons. With only four copies of each tile existing, holding a pung means you control three of the four.

A pung can be concealed (anko), formed entirely from tiles you drew yourself, or open (minko), completed by claiming an opponent's discard with a 'pon' call. The distinction matters a great deal for scoring. In Japanese riichi, a concealed triplet of terminals or honors is worth far more fu than an open one, and certain yaku like sanankou (three concealed triplets) require the pungs to be closed. In Chinese and Hong Kong styles, concealed pungs and especially pungs of dragons or your seat/round wind add bonus points or faan.

One common confusion is that claiming a tile to make a pung opens your hand, which can disqualify riichi and reduce the value of many hands, so experienced players weigh the tempo gain against the scoring loss. Another is the difference between a pung and a kong: a kong is four identical tiles and still counts as a single set, but it draws a replacement tile and reveals a new dora indicator in riichi.

For example, if you hold 5p-5p and an opponent discards 5p, calling pon completes 5p-5p-5p as an open pung; if instead you draw the third 5p yourself, you keep a more valuable concealed triplet.