A "Pung" is three identical tiles.
There are two ways to make a Pung:
By picking up a tile discarded by any player, if a Pung this made this way it is known as an Exposed Pung and it will be placed above a player's stake for all other players to see. The hand will then continue from the player who has made the Exposed Pung.
You can make Pungs if you wish from tiles you have been dealt. If you do this the Pung is known as a Concealed Pung and can stay in your hand.
A player can turn an Exposed Pung into an Exposed Kong only if the player is DEALT a tile that is identical to the tiles in the Exposed Pung. When this happens the Exposed Kong will be displayed above the player's stake and the player will be dealt a replacement tile. The Game then continues from the player who has just made the Exposed Kong.
There are some circumstances when you are not allowed to pick up a discarded tile to make a Pung. This occurs when two or more players want to pick up the same discarded tile. See Precedences for more information.
See also Rules.