Naki strategy

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Calling tiles is optional. During a game, players must constantly decides whether to call tiles or not - this decision warrants at least a little observation and evaluation. This page only considers pon and chi, not kan. For strategy regarding kan, see kan strategy.

Assessing calls

Like any decision in the game, opening the hand has advantages and disadvantages.

Advantages

• Allows the hand to complete faster. Sequences can be completed with twice the number of tiles (self draws, and the left opponent's discards). Triplets can be completed with four times the number of tiles (your draws, anyone else's discards).
  • Can be used to confirm a yaku. Yakuhai, for instance, are hard to complete without calling pon.
  • Can be used to complete a hand you otherwise wouldn't have completed at all. If a hand has 12-man, and the last 3-man is discarded, the sequence will be impossible to complete without a call.
• It is hard for opponents to know whether an open hand is complete or not.
• Disrupts an opponent's ippatsu and affects who gets the haitei draw.
  • On the first turn, calls can disrupt chiihou, double riichi, and the option to call kyuushu kyuuhai.
  • Can also disrupt an opponent's nagashi mangan.

Disadvantages

• Opening the hand prevents certain yaku, most importantly riichi.
  • Lowers the value of other yaku, such as sanshoku and ittsu.
  • The hand must have at least one yaku in order to win; it cannot rely on riichi to gain a yaku.
• Reduces the amount of tiles available to discard, making it harder to defend.
• Reveals the called tiles to your opponents, possibly allowing them to deduce the value/contents/yaku of that hand.

Yaku

Main article: List of yaku

In order for a hand to win, it must have at least one yaku. Closed hands can always call riichi, but open hands need something else. Tanyao and yakuhai are the easiest/most common of the open yaku; in tenhou.net's houou room, over 90% of all open hands contain one or the other. Other common candidates (from most frequent to least) include: honitsu, toitoi, sanshoku doujun, chanta, and ittsu.

A hand with an unconfirmed yaku may end up in atozuke, a state where the hand only has yaku when it wins off a certain tile. For example, a tanyao-only hand with a "78" wait can only win with a 6, since 9 ruins tanyao. This can lead to furiten if the wrong winning tile is drawn.

Value

Once a hand reaches 4 han, every han afterwards is reduced in value. So if a hand has 4+ guaranteed han after opening, it's often best to call. At this point, the extra speed from calling is often worth the drop from value.

When a hand is cheap, the opposite effect can occur. If a hand would be 1 han (riichi-only) when closed, or 1 han when opened, going open is often better. This mostly happens with yakuhai pairs - keeping the pair ruins tanyao and pinfu, but pon gives 1 han through the yakuhai triplet. Even when considering the score bonuses from riichi (ippatsu, uradora, mentsumo), an open hand's increased speed is often better than the chance for extra points.

Point standings

As with most things in riichi mahjong, the game's specific point standings will alter the need to call. If 12k points are needed to escape 4th in all last, it is best to stay closed even with a 4 guaranteed han hand. If you need 1k points in all last, call as soon as a yaku is available.

Tenpai Settlements

Main article: Ryuukyoku

After all tiles in the live wall have been drawn, players in noten pay those in tenpai. In addition, depending on the rules, dealers get to keep their seat if they are in tenpai. Therefore, players near the end of the game may wish to call tiles to reach tenpai.

Even if a hand would have no yaku, or would be otherwise impossible to complete, players can still call tiles in order to reach keishiki tenpai ("shaped tenpai"). For the purposes of tenpai settlements, a hand in keishiki tenpai still counts like any other tenpai.