Two Games Built From the Same Tiles

American Mahjong and Japanese Riichi Mahjong both descend from the same Chinese game, and both still use recognizably the same suits: Characters (Manzu), Circles (Pinzu), Bamboo (Souzu), winds, and dragons. Photographs of the two tile sets look broadly similar.

Almost everything built on top of those tiles diverged. American Mahjong, standardized by the National Mah Jongg League (NMJL), has been played in the United States since the 1920s boom and supports organized tournaments, casino events, and themed cruises. Japanese Mahjong developed on its own track for roughly a century, and international players usually call it Riichi Mahjong specifically to distinguish it from every other version.

The next two sections explain how each game is actually played, so the comparison that follows makes sense even if you have never played either one.

American Mahjong: How the Game Works

American Mahjong is played by four players using a 152-tile set. Each player receives 13 tiles, and the dealer receives 14.

The Goal

Every year the NMJL publishes an official card listing the exact hands that are legal to win with that year. A player's goal is to assemble one of those listed hands precisely. Nothing outside the card counts, no matter how impressive it looks.

Because the card is reissued annually, players buy the current version each year, and part of the skill is knowing what is on it.

The Flow of a Hand

• Charleston. Before play begins, all four players trade tiles in a structured exchange. This is explained in detail further down.
• Draw and discard. Play then proceeds around the table. On each turn a player draws a tile and discards one.
• Calling. A discarded tile can be claimed to complete a pung (three of a kind) or kong (four of a kind). Claimed sets are exposed on the rack for everyone to see.
• Jokers. Eight jokers act as wild tiles and can stand in for other tiles within a group, which is what makes the card's demanding hands reachable.
• Winning. A player who completes a hand on the card declares Mahjong. The value is printed next to that hand on the card.

What the Game Feels Like

American Mahjong is a race to complete a fixed target. Tiles are held on racks rather than stood on the table, and the social, conversational atmosphere is a defining part of how it is played in clubs and tournaments.

Japanese Riichi Mahjong: How the Game Works

Riichi Mahjong is played by four players using a 136-tile set. There are no flowers and no jokers. Each player receives 13 tiles, and the dealer receives 14.

The Goal

A winning hand is normally four sets plus one pair, using 14 tiles. A set is either a sequence (three consecutive numbers in the same suit, such as 3-4-5 of Circles) or a triplet (three identical tiles).

There is one additional requirement that defines the game: the hand must also contain at least one yaku, a named scoring pattern. A hand that is structurally complete but has no yaku cannot be declared a win. The yaku list is fixed and does not change from year to year.

The Flow of a Hand

• Draw and discard. Play proceeds counter-clockwise. On each turn a player draws a tile and discards one.
• Calling. A discard can be claimed for a triplet (Pon), a quad (Kan), or — only from the player on your left — a sequence (Chi). Calling speeds a hand up but closes off the yaku that require a concealed hand.
• Winning. A hand can be completed by self-draw (Tsumo) or by claiming another player's discard (Ron).
• Riichi. When a concealed hand is one tile from completion, the player may declare Riichi, betting a 1,000-point stick and locking the hand in exchange for extra scoring potential.
• Scoring. Value is calculated from the hand itself using han and fu, rather than read off a list.

Match Structure

Hands are grouped into rounds. The most common format, a hanchan, runs an East round and a South round, and players start with a set number of points that move between them as hands are won and lost. Final placement is decided by points at the end.

A full step-by-step guide is available in how to play Japanese Riichi Mahjong.

The Tiles: 152 vs 136

An NMJL set contains 152 tiles: the 136 suit and honor tiles, 8 flowers, and 8 jokers. A Japanese Riichi set contains 136 tiles only.

That difference shapes both games. Eight wild tiles make highly specific, demanding hands realistically completable. With no wild tiles at all, every tile in a finished Riichi hand has to be the tile the hand actually requires.

The Same Tiles Under Different Names

American sets renamed several tiles for players unfamiliar with Chinese characters. Hatsu became the Green Dragon and Chun the Red Dragon, names that carried into English-language Riichi usage as well. The white dragon took a different path: in American Mahjong it is the soap, and it doubles as a zero in year hands such as 2025. In Riichi it is simply Haku, a yakuhai tile worth one han as a triplet, with no numeric role.

Physical Differences

American tiles are noticeably thinner and are designed to sit in a rack, usually paired with a pusher. Japanese tiles are thicker and stand on their own on the table surface, which is why racks never became standard in Japan.

Japanese play also has no flowers to set aside and no jokers to track, so the table stays visually simpler. Many Japanese players use an automatic table that shuffles the tiles and builds the walls, removing most of the setup between hands.

The Charleston: Trading Tiles Before Play

The Charleston is the most distinctive feature of American Mahjong. After the deal, and before play begins, all four players exchange tiles simultaneously:

• Pass three unwanted tiles to the player on the right, and receive three from the left.
• Pass three across to the player opposite, and receive three back.
• Pass three to the player on the left, and receive three from the right.

That sequence counts as one Charleston. If all players agree, a second Charleston runs in the opposite direction. Jokers may never be passed. The purpose is simple: exchanging tiles makes the demanding hands listed on the card achievable.

Riichi Mahjong has no equivalent. Players are dealt a hand and play it. Trading tiles with another player is not an optional rule variation; it would be cheating.

This changes how each game opens. In American Mahjong the Charleston lets a player commit to a target hand early, because the tiles can be actively shaped toward it. In Riichi the first several turns are spent reading what the dealt hand is capable of and staying flexible while the shape declares itself. Committing too early to one finished hand is a common beginner error in Riichi, precisely because there is no mechanism to correct course.

How Hands Are Built: The Card vs Yaku

This is the deepest structural difference between the two games.

American Mahjong: Match the Card Exactly

Hands are built almost entirely from pungs, kongs, pairs, and singles — groups of identical tiles. Some hands also call for quints, five of a kind, which are only reachable with jokers.

Crucially, American Mahjong has essentially no sequences. There is no Chi call, and three consecutive numbers in one suit is not a building block. A winning hand must match one listed combination exactly, and the set of legal targets is replaced every year.

Riichi Mahjong: Shapes, Not a List

Riichi runs the opposite way. Sequences are not merely permitted; they are the backbone of most hands. Because a set can be either a sequence or a triplet, and because tiles can be rearranged mentally into different combinations, a Riichi hand is rarely locked to one outcome until late.

The skill is therefore reading which shapes accept the most useful tiles — keeping a 4-5 that completes with either a 3 or a 6, rather than a 4-6 that only completes with a 5. This is called tile efficiency, and it is the core study topic for improving players.

For the full list of scoring patterns, see the complete Mahjong yaku list with tile samples.

Scoring, Riichi, and Dora

In American Mahjong, the value of a hand is printed next to it on the card. The payout is known before building starts, so the strategic question is which listed hand to pursue.

Riichi calculates value from the hand that was actually made, using han (doubles contributed by yaku) and fu (minor points from hand composition). Two players can complete hands of the same shape and be paid very differently depending on which yaku apply, whether the hand stayed concealed, and how many bonus tiles it contains.

Declaring Riichi

The mechanic the Japanese game is named after has no American counterpart. Declaring Riichi announces to the table that the hand is one tile from completion. In exchange for locking the hand — its shape can no longer change — the player gains scoring value and access to bonus yaku.

The declaration is public information, and that is part of its design. Everyone else must now decide whether to keep attacking or switch to safe discards.

Dora

Dora are bonus tiles indicated at the start of each hand. Holding them multiplies the score, but dora is not a yaku. A hand full of dora with no yaku still cannot win — a rule that surprises players used to systems where any high-value combination is automatically payable.

Defense: Where the Two Games Diverge Most

Tile counts and hand lists are the visible differences. This is the one that changes how the game is actually played.

American Mahjong is fundamentally a race. Each player builds toward a hand on the card, calls what they need, and the first completed hand wins. There is no meaningful penalty for discarding the tile someone else was waiting on.

Riichi Mahjong has deal-in. Discarding the exact tile an opponent is waiting on lets them win on that discard, and in most cases the discarder personally pays the entire score. One careless discard against a large hand can cost more than several wins are worth.

That single rule creates an entire second half of the game:

• Reading discards. Every tile an opponent discards narrows down what they can be waiting for.
• Safe tiles. A tile already sitting in an opponent's discard row cannot be won on by that opponent, which makes it safe against them.
• Folding. When a hand cannot realistically win and an opponent is clearly ready, strong players abandon their own hand entirely and discard only safe tiles until the hand ends.

Folding is the part that feels least natural to players arriving from a race-style game, and pushing too often is the most common leak among newer Riichi players. The techniques for identifying safe tiles are covered in Suji and Kabe: how to find safe tiles when facing Riichi.

How the Two Traditions Influenced Each Other

The exchange has not been one-directional. Riichi's Seven Pairs (Chiitoitsu) — a hand of seven distinct pairs rather than four sets and a pair — is widely described as a pattern that American Mahjong popularized before it settled into the Japanese yaku list. Given how pair-driven NMJL hands are, that lineage is easy to believe.

One point is worth correcting, because it circulates often: Riichi itself is Japanese, not American. The declaration developed within Japan through the mid-twentieth century, with an early form appearing in the late 1940s and the ruleset that shaped the modern game published in 1952. It was not an import.

The broader picture is that mahjong is unusual among classic games in how thoroughly it localized. Japan, China, Hong Kong, Taiwan, and the United States each developed genuinely different games from the same tiles. For the wider survey rather than this head-to-head, see Japanese Riichi Mahjong vs other versions.

Quick Reference Summary

The practical differences at a glance.

Final Thoughts

Placed side by side, American Mahjong and Japanese Riichi Mahjong turn out to be two distinct games wearing the same tiles. One is built around a published list of target hands, wild tiles, and a tile-trading opening. The other is built around flexible sequences, a fixed yaku list, and the constant risk of paying for a bad discard.

Neither structure is a simplified version of the other. American Mahjong asks for pattern memory and creative use of jokers; Riichi asks for shape recognition and disciplined risk assessment. Players who enjoy one often find the other rewarding for the opposite reasons.

Anyone moving between them will find the tiles instantly familiar and the decisions entirely new — which is arguably the most interesting thing about mahjong as a global family of games.