Naki

Naki (鳴き) are legal claims on discarded tiles. In other words, these are the tile calls:

Chii	チー	Sequences
Pon	ポン	Three-of-a-kind
Kan	カン	Four-of-a-kind

Mentsu and overview

Main article: Mentsu

As a general rule, tile calls apply to the tile immediately discarded. Naturally, players are not required to claim discarded tile; but they may do so under the condition of possessing 2 out of 3 tiles for a meld in the hand. Every discarded tile not claimed by discard remain in the discard piles, until the end of the hand.

In addition, kuikae is an additional rule to tile calls. Players may have melds within the hand; and a discarded tile may allow a tile claim. If a player wishe to create an open meld using parts of an existing meld, then a player is not allowed to discard the remainder of the meld, until one full turn later.

Chii

Chii is applied for opening sequential melds, to form minjun.

Pon

Unlike "chii", the call for pon may be called from any player on the board. Toitsu, or pairs, may be upgraded to minkou, or open triplets.

Kan

Main article: Kan

Kan works like pon, except this call has some added procedures.