Naki

Naki 「鳴き」 are legal claims on immediately discarded tiles. The instant a discarded tile is declined for a claim, then it goes out of play and remains in the discard pile until the next hand. Discarded tiles gives players another source of tiles for hand completion, other than the regular wall. Upon claiming a discard, the player's hand is then considered to be open. As a consequence, the player loses the option to call riichi, and the hand is not eligible for the yaku, mentsumo. In addition, certain yaku decreases in value by 1-han, when opened.

Yet, players may benefit from open tile calling from increasing the speed of hand development, convenience, or the irrelevance of losing hand value by opening. Players must also consider the number of tiles available. Overall, tile calling is a discretionary move. Especially with hands valued of mangan or greater, opening the hand may be a better option than keeping it closed.

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.

Tile calls

Chii	チー	Sequences
Pon	ポン	Three-of-a-kind
Kan	カン	Four-of-a-kind
Ron	ロン	Win on discard

For each immediate discard, players have the option to make claims on discarded tiles based on the following conditions:

• For all claims, a player must have 2 out of the 3 tiles in the hand necessary to form a complete meld.
• Discard claims must be made immediately after discard, and before the next player's turn. Otherwise, a discarded tile remains in the discard pile and may not be claimed.
• Players reveal their two tiles and append the claimed tile. Then these three revealed tiles are placed to the right corner of the player's area.
• The claimed tile must be arranged sideways to indicate the claimed tile.
• The claimed tile must be arranged on the left, middle, or right to indicate the source of the claim.
• The open tile call notation helps with the enforcement of furiten, as claimed tiles are still noted as part of player discards.
• If the discarded tile completes a hand, then any player may call ron.

Chii

Chii is applied for opening sequential melds, to form minjun. To claim and complete sequences, the player to the right of the discarder may claim the tile and call chii. This means, any player calling chii may only claim tiles from the player to the left. Therefore, the tile turned sideways is always indicated on the left.

Pon

Left	Across	Right

Toitsu, or pairs, may be upgraded to minkou, or open triplets. Unlike "chii", the call for pon may be called from any player on the board. As long as a player possess two identical tiles and a third is discarded, the player may call for that discarded tile regardless. Because any player may call, sometimes a player's turn may be skipped.

Kan

Main article: Kan

Kan may work like pon, except this call has some added procedures and additional situations. Likewise, the tile arrangements works similarly to pon. However, there is the addition of the other two kan types: ankan and shouminkan. Unlike the other tile calls, kan has some specific rules applied. Mostly, these relate to the dead wall. In addition, two yaku, (rinshan and chankan), are particularly associated with kan.

Ron

Ron is a specific tile call on a discard, when the discard actually completes the hand. Also, the hand must have a valid yaku. Ron may be called during furiten, but the call becomes subject to chombo.

Call precedence

The different tiles calls take precedence.

1. Ron
2. Kan
3. Pon
4. Chii

It is impossible for kan and pon to be called simultaneously. However, either can simultaneously occur with chii. Due to precedence, the player, who calls kan or pon, gains the right to a discarded tile over a chii call. Overall, the call for ron supercedes all tile discard calls.

Open vs closed

With regards to mahjong hands, the common question looks to determine the best practices of opening or closing a hand. For starters, players should know the yaku and their han values. Essentially, this begs the question: "Is it worth opening the hand, or is it better to remain closed?" Naturally, there are advantages and disadvantages to either approach. For both cases, the speed at which a hand attains tenpai rests on this decision.