Riichi Mahjong

1 History and Origins

Riichi Mahjong (リーチ麻雀, also called Japanese Mahjong or Reach Mahjong) developed in Japan during the mid-20th century. Japanese players adapted Chinese Mahjong rules, streamlining some elements while adding distinctive features that make Riichi Mahjong one of the most strategically deep variants in the world.

The key innovations: the Riichi declaration (betting 1000 points to declare a ready closed hand), the dora indicator system (bonus tiles that add value without constituting yaku), the furiten rule (preventing certain won positions from discarding then claiming back), and the strict requirement that every winning hand must have at least one yaku. These changes together create a game where hand reading, risk management, and tile efficiency are paramount.

Riichi Mahjong is the dominant form in Japan and has a massive online following worldwide, especially through platforms like Mahjong Soul (Jantama) and tenhou.net. It is also the format used in most international Mahjong tournaments outside East Asia.

2 The Tiles (136 Total)

No flower or season tiles. 136 tiles total.

Suited tiles (108):

• Man (Characters / Manzu): 1-9, four copies each (36 tiles). Japanese term: 一二三四五六七八九萬
• Pin (Circles / Pinzu): 1-9, four copies each (36 tiles).
• Sou (Bamboo / Souzu): 1-9, four copies each (36 tiles).

Honor tiles (28):

• Wind tiles (16): East (ton), South (nan), West (sha), North (pei). Four each.
• Dragon tiles (12): Haku (White, 白), Hatsu (Green, 發), Chun (Red, 中). Four each.

Red fives (optional): Many sets include one or more red 5 tiles (akadora) in each suit, which count as dora and add han to the hand value. Common in competitive play.

3 Setup

1. Shuffle 136 tiles. Each player builds a wall of 34 tiles (2 high, 17 wide).
2. The dealer (East) is determined. Seat order counterclockwise: East, South, West, North.
3. Break the wall: dealer rolls dice, counts from the right end of the East wall. The dead wall is the last 14 tiles to the right of the break (7 stacks of 2).
4. Deal 13 tiles to each player (4 at a time, three rounds, then 1 each). Dealer takes one extra tile, giving 14 tiles, and discards to begin.
5. Turn over the first dora indicator: flip the third tile from the right end of the dead wall face up. The tile one higher (wrapping 9-to-1 and North-to-East for winds, Chun-to-Haku for dragons) is the current dora. Every dora tile in your winning hand adds 1 han.
6. Starting points: each player begins with 25,000 points (common standard; varies by rule set). Each player places 1000 points in front as an initial "deposit" for the session in some rule sets.

4 Turn Structure

Play moves counterclockwise. On your turn:

1. Draw: Take one tile from the live wall.
2. Win or continue: If your drawn tile completes a valid hand with at least one yaku, declare Tsumo (self-draw win). Otherwise, discard one tile.

After each discard, opponents may:

• Ron (win): Claim the discard to complete a valid winning hand. Highest priority.
• Kan (kong, 4 of a kind): Any player may claim a discard to complete a kan. Draw a replacement from the dead wall and reveal a new dora indicator.
• Pon (pong, triplet): Any player may claim for a pon.
• Chi (chow, sequence): Only the player whose turn comes next may claim a chi.

Claiming pon or chi opens your hand (makes it "open" or "called"). An open hand cannot declare Riichi and has fewer available yaku (many yaku require a closed hand). This is the central tension of Riichi Mahjong: speed via calls vs. hand quality via closed play.

5 Yaku (Hand Qualifiers)

Every winning hand must contain at least one yaku. A hand with zero yaku cannot win, even if structurally complete. Yaku are scored in han (doubles). Some yaku lose value or disappear when the hand is open (called). "Closed only" means the yaku only counts in a fully concealed hand.

Yakuman (Maximum Value Hands)

Yakuman hands score the maximum point value in a single hand (typically 32,000 from dealer or 16,000 from each non-dealer for a self-draw). Some rule sets allow double yakuman.

• Kokushi Musou (Thirteen Orphans): One each of 1m, 9m, 1p, 9p, 1s, 9s, East, South, West, North, Haku, Hatsu, Chun plus a duplicate.
• Suuankou (Four Concealed Triplets): Four concealed triplets, closed hand, tsumo win only (double yakuman if won with a shanpon/dual-pair wait).
• Daisangen (Big Three Dragons): Triplets of all three dragon tiles.
• Shousuushii / Daisuushii (Small/Big Four Winds): Triplets of three winds plus the pair of the fourth wind (small), or triplets of all four winds (big, double yakuman).
• Tsuuiisou (All Honors): Entire hand of wind and dragon tiles.
• Ryuuiisou (All Green): Hand uses only 2s, 3s, 4s, 6s, 8s Sou and/or Hatsu (all tiles have green in their design).
• Chinroutou (All Terminals): All triplets of only 1s and 9s.
• Chuuren Poutou (Nine Gates): 1-1-1-2-3-4-5-6-7-8-9-9-9 in one suit, closed.
• Suukantsu (Four Kans): Four kans plus a pair.
• Tenhou / Chiihou (Heaven/Earth): Dealer wins on initial draw (Tenhou), or non-dealer wins on their first draw before any claims (Chiihou).

6 Riichi Declaration

Riichi is the signature feature of this style. You may declare Riichi when:

• Your hand is tenpai (one tile away from winning).
• Your hand is completely closed (no open melds from claimed discards).
• You have at least 1000 points to bet.

To declare Riichi:

1. Place 1000 points in front of you on the table (the Riichi bet).
2. Discard your tile sideways to indicate the Riichi discard.
3. Your hand is now locked. You must draw and discard without changing your hand. You can only win on tiles that complete your pre-declared winning condition. If you draw a tile that would complete your hand, you must win immediately (Tsumo) or discard it. If you draw a tile that could be a useful tile for a different shape, you must discard it (you cannot change your wait).

Benefits of Riichi: +1 han; Ippatsu possibility (+1 han if you win in the first go-around after declaring); Ura-dora reveals (additional dora indicators flipped from the dead wall after your win).

Risk of Riichi: Your hand is locked, so you cannot respond to opponent's tiles. You also signal to opponents that you are ready, which may affect their discard choices.

Double Riichi (Daburu Riichi): Declare Riichi on your very first discard of the game. Worth 2 han instead of 1. Extremely lucky but powerful.

7 Dora System

Dora tiles add han to your hand but are NOT yaku by themselves. You still need at least one legitimate yaku to win.

Dora indicator: The third tile from the right of the dead wall (shown face-up from the start). The actual dora is the tile one higher in sequence:

• Suit tiles: 1-dora-indicator means 2 is dora; 9-dora-indicator means 1 is dora (wraps).
• Winds: East indicator means South is dora; North indicator means East is dora (wraps East-South-West-North-East).
• Dragons: Haku indicator means Hatsu is dora; Chun indicator means Haku is dora.

Kan dora: Every time a kan is declared, a new dora indicator is flipped from the dead wall, adding another potential dora tile.

Ura-dora (裏ドラ): After a Riichi win, the tiles immediately below each face-up dora indicator are revealed as ura-dora. Each ura-dora tile in the winner's hand adds 1 han. Ura-dora only applies to Riichi winners.

Akadora (Red fives): Many competitive sets include one red 5 in each suit (sometimes two red 5-pins). Each red five in your winning hand counts as 1 dora, regardless of the current dora indicator.

8 Furiten Rule

Furiten (振聴) is a rule that prevents winning by Ron (off a discard) when you are in certain waiting states. You are in furiten if any of these apply:

• Your own discard: Any tile in your current winning wait is in your own discard pile. You cannot win by Ron on tiles you previously discarded. (You can still win by Tsumo.)
• Missed discard: A tile that would have completed your hand was discarded by an opponent and you did not claim it (even if you did not want it). You are in temporary furiten until your next discard. (Tsumo is still available.)
• Riichi furiten: If you are in Riichi and miss a winning tile, you are permanently in furiten for that hand (cannot win by Ron for the rest of the hand).

Furiten does NOT prevent Tsumo wins. It only affects Ron (winning off a discard).

9 Scoring: Han and Fu

Riichi Mahjong scoring is based on two values: han (doubles) and fu (base points).

Han

Han is the count of doubles applied to the hand. Each yaku contributes a certain number of han. Dora adds han. The total han determines the scaling factor.

Fu

Fu is a base point count determined by hand structure. Common fu sources:

• Base fu: 30 fu for a closed Ron win, 20 fu for a Tsumo or open Ron
• Sequence melds: 0 fu
• Open triplet of simples (2-8): 2 fu
• Concealed triplet of simples: 4 fu
• Open triplet of terminals/honors: 4 fu
• Concealed triplet of terminals/honors: 8 fu
• Open kan of simples: 8 fu
• Concealed kan of simples: 16 fu
• Open kan of terminals/honors: 16 fu
• Concealed kan of terminals/honors: 32 fu
• Pair of value tiles (dragon, seat/round wind): 2 fu
• Winning wait: single tile wait = 2 fu; closed pair wait = 2 fu; edge wait (1-2 waiting on 3, or 7-8 waiting on 9) = 2 fu; standard two-sided wait = 0 fu
• Tsumo: 2 fu (then each opponent pays rounded amount)

Fu is rounded up to the nearest 10.

Payment Table (Common Values)

Payment = base_points x 2^(han+2), rounded up to nearest 100. For a Ron win, discarder pays all. For Tsumo, dealer pays double what non-dealers pay.

Tsumo values shown as non-dealer pays / dealer pays. All values are for standard 30 fu; actual values depend on fu calculation.

Honba (Counter Sticks)

Each time the dealer retains the seat (by winning or by a draw), a honba counter increases by 1. Each honba adds 300 points to the total payment (100 per player for Tsumo). Honba accumulate and reset when a non-dealer wins.

Chombo (Penalty)

A chombo is a penalty for an illegal declaration. Causes include: declaring a winning hand that is not actually complete, being in furiten and claiming Ron, or drawing from the wrong part of the wall. Chombo typically means paying each opponent the mangan value (8,000 non-dealer, 12,000 dealer) and the hand is voided.

10 Strategy

Tile Efficiency (Ukeire)

The core skill in Riichi Mahjong is maximizing the number of tiles that advance your hand toward tenpai. Each discard should be evaluated by how many tiles in the wall improve your hand (your "uke-ire count"). High uke-ire means you get to tenpai faster.

Yaku Planning

Know your yaku before you have 13 tiles. Common beginner paths: Tanyao (all simples) is fast and works open. Riichi requires closed hand but adds 1 han plus potential ura-dora. Yakuhai (dragon/wind triplet) can be the foundation of an open hand. Pinfu (all sequences, two-sided wait) is efficient and pairs well with Tanyao in a closed hand.

Reading the Table

Track all discards to infer opponents' hands. Tiles they have discarded are safe to discard back to them (they passed on them once). Tiles in the same number or suit as recent discards are often relatively safe. Dangerous: tiles adjacent to what opponents are keeping; isolated tiles mid-game.

Defense

When an opponent declares Riichi, your priority shifts to defense. Discard only provably safe tiles (tiles already in their discard pile, tiles that cannot complete anyone's hand). If you have no safe tiles, consider folding and absorbing a small loss rather than dealing into a large hand.

Riichi Timing

Declaring Riichi is not always the best move even when available. A good tenpai hand with Riichi will score well. But an open hand with guaranteed yaku that can adapt to the game state may be more valuable late in the round when the wall is short.

11 Common Misconceptions

• "A complete hand wins." Wrong. You must have at least one valid yaku. Dora tiles alone are not yaku. A hand with only dora and no yaku cannot win.
• "Riichi means you win." No. Declaring Riichi puts 1000 points at risk. If another player wins the hand first, you lose that bet. If no one wins, you get it back.
• "Furiten only matters for your own discards." Wrong. Furiten also applies if you pass on a discard that would have completed your hand (temporary furiten until your next discard).
• "Open hands are weaker." Not always. An open Honitsu (half flush) or Toitoi (all triplets) can score very well. The trade-off is losing access to closed-only yaku like Riichi and Pinfu.
• "You can swap what you discard after Riichi." Absolutely not. Your hand is locked after Riichi. You draw and must discard any tile that is not your winning tile(s). You cannot change your tenpai wait.

12 Frequently Asked Questions

What does tenpai mean?

Tenpai means your hand needs exactly one more tile to be complete. You are "ready" or "in hand." Being in tenpai is required to declare Riichi.

What is noten and noten payment?

At the end of a round with no winner, players reveal whether they are in tenpai (noten = not in tenpai). Players in tenpai collectively receive 3,000 points from players in noten, split evenly.

Can I declare Riichi with an open hand?

No. Riichi requires a fully closed hand (no melds claimed from discards).

What is ippatsu?

Ippatsu is a bonus yaku (+1 han) awarded if you win within one complete go-around of the table after declaring Riichi, before anyone else discards or makes a claim that "breaks" the ippatsu window.

How many han do I need to win?

Technically just 1 han (with enough fu). But the minimum scoring win (1 han 30 fu) is worth 1000 points from Ron. Most meaningful wins are 2+ han.

What is chombo?

Chombo is a penalty hand. If you make an illegal declaration (false win, Ron while in furiten), you pay each opponent a mangan-equivalent payment and the hand is void.

What is yakitori?

A side rule where players who have not won a single hand during the entire game must pay a penalty at the end (often 1000-10,000 points, marked by a yakitori marker). Not used in all rule sets.

What are ura-dora?

Ura-dora are hidden dora indicators revealed only after a Riichi winner is declared. The tile directly below each visible dora indicator is flipped; the tile one higher from each ura-dora indicator is an additional dora for the Riichi winner.

Can I win off my own discard?

No. You can only win by Tsumo (drawing your own winning tile) or by Ron (claiming another player's discarded tile that completes your hand).

What happens to unclaimed Riichi bets?

Unclaimed Riichi bets from a drawn round remain on the table and are claimed by the next winner of a subsequent hand.