The History of Online Mahjong (Riichi Online and More)

“Mahjong” online means two completely different things to two different audiences. Western readers mostly think of Mahjong Solitaire — the single-player tile-matching game popularized by Microsoft’s Mahjong package. East Asian players almost always mean the four-player gambling game with a 137-tile wall, a thousand-year history (well, more like a hundred and fifty), and a competitive scene. The history of online mahjong covers both, but the more interesting story is how the four-player game found a global audience through the web.

The game and its versions

Mahjong as a four-player game is played with 136 or 144 tiles (the count depends on the ruleset). Players draw and discard tiles trying to assemble a winning hand of four sets plus a pair. The most popular ruleset internationally is Riichi Mahjong — the Japanese version — which adds a betting/declaration mechanic (“riichi”) and a complex scoring system based on yaku (winning conditions). Chinese Mahjong (multiple regional variants), Hong Kong Mahjong, and American Mahjong are all played but have smaller online presences.

Mahjong Solitaire is something completely different. It’s a single-player tile-matching puzzle where the player removes matching pairs of tiles from a pyramidal layout (the Turtle is the canonical shape). It uses Mahjong’s tiles but none of its rules. It was designed by Brodie Lockard in 1981 and popularized on Mac and PC. The two games share tiles and nothing else.

Early online Mahjong: the late 1990s and 2000s

Real four-player Mahjong moved online in Japan in the late 1990s. Computer Mahjong games had existed since the early 1980s (Mahjong was a top arcade and home computer genre in Japan throughout that decade), but networked play came later. East Mahjong, also known as Tonpuusou Online, was one of the first widely-played Japanese services in the late 1990s. Korean and Chinese Mahjong servers followed soon after, mostly running Chinese rule variants.

By the early 2000s, Japanese-language Mahjong servers had carved out a substantial user base. Ron2, MJ.Net, and several others competed in the space. None of these reached Western audiences in any meaningful way; the language barrier and the unfamiliarity of Riichi rules kept the player base regional.

Tenhou (2006) and the Japanese standard

Tenhou launched in 2006, developed by a programmer known by the handle Tsumegoro. It became the dominant Japanese Riichi Mahjong server within a few years and held that position for over a decade. Tenhou’s appeal was its strict matchmaking, its rating system (the famous Tenhou rank, with Houou — Phoenix — table as the high-rank goal), and its no-frills interface. It looked spartan because it was meant to be played, not decorated.

Tenhou is also free, which mattered. Pro Mahjong organizations in Japan adopted Tenhou as their unofficial training platform. Top human players streamed games. Beginners watched. The combination produced a competitive ecosystem with a clear top — Houou tables — that the broader Japanese Mahjong community accepted as canonical.

Tenhou never seriously courted non-Japanese audiences. The interface is Japanese-only. Foreigners played it through fan translations and crash courses, but the barrier was high. For more than a decade, Western Riichi Mahjong was a small expat-and-anime-fan community.

Mahjong Soul (2018) and the global push

Mahjong Soul (Jantama in Japanese, originally launched as Mahjong Mahjong in Chinese) was released in 2018 by CatFood Studio in China and operated globally by Yostar. The English-language client launched a year later. Mahjong Soul did what Tenhou never tried: it made Riichi Mahjong approachable to a global audience.

The design was deliberately friendly. Mahjong Soul has anime-styled character avatars, a flashier UI, tutorial sequences, a clear progression system, and gacha mechanics for cosmetic unlocks. Underneath, the rules and scoring are standard Riichi. The result was a flood of new Western players. Mahjong streamers — Daina Chiba, Riichi Book Translation, others — saw their audiences grow. The English-language Mahjong community grew from a small enthusiast core to something substantially larger.

Mahjong Soul also surpassed Tenhou in absolute player count by the early 2020s, including in Japan. Tenhou remains the canonical competitive server, but Mahjong Soul is where the majority of casual and intermediate players spend their time. For broader genre context, see our roundup of games like Mahjong.

Riichi.com and the English-language scene

Riichi.com (formerly run as Reach Mahjong) and a handful of Discord-based communities support the English-speaking Mahjong scene. The site hosts ratings, tournaments, and educational content. The World Riichi Championship — a real-life tournament organized by the European Mahjong Association and partners — has held events since 2014, and the online qualifiers funnel through these communities.

The educational layer matters because Riichi Mahjong is harder to learn than its surface suggests. The mechanics (draw a tile, discard a tile, try to make sets) are simple. The scoring system, the yaku list, and the strategic depth around defense and folding are not. English-language resources — books like “Riichi Book 1” by Daina Chiba, dozens of YouTube tutorial channels, the EMA’s rule documents — exist because Mahjong Soul brought enough new players in to support them.

Mahjong Solitaire’s separate history

The single-player Mahjong tile-matching game has its own online history. The original — Mahjongg by Brodie Lockard, released in 1981 — was the basis for endless variants over four decades. Microsoft Mahjong shipped with Windows Vista and Windows 7 (replacing the older Mahjongg game from Microsoft Entertainment Pack), and Microsoft Mahjong continued through Windows 8, 10, and 11.

Web versions of Mahjong Solitaire are everywhere. Mahjong.com, ArkadiumMahjong, and dozens of free sites host the tile-matching format. The game is well-suited to a browser: small state, click-based input, low compute. It’s one of the puzzle genres most consistently played online over the last 25 years.

Why online changed Riichi Mahjong

Before online play, Riichi Mahjong required four people, a Mahjong table (often an electric auto-shuffling one in Japan), and the willingness to commit to a multi-hour session. Online turned a four-player coordination problem into a one-click experience. That single change is most of why the game’s player base has grown so much over the last decade.

It also changed the game’s pace. Online sessions can be East-only (Tonpuusen, roughly 20-30 minutes) instead of full Hanchan (East and South, 50-60 minutes). The shorter format lowered the time commitment. The strategic implications are real — East-only encourages more aggressive play, since defending positions over a longer game is less valuable when the game ends sooner. Mahjong purists argue this is a corruption of the form. The numbers show players prefer the option.

Frequently asked questions

What’s the difference between Mahjong and Mahjong Solitaire?

Mahjong is a four-player tile game with hand-building, sets, and scoring. Mahjong Solitaire is a single-player tile-matching puzzle that uses the same tiles but completely different rules. They share artwork and almost nothing else.

When did Tenhou launch?

Tenhou launched in 2006, developed by a programmer with the handle Tsumegoro. It became the dominant Japanese online Riichi Mahjong server within a few years and is still operating.

Is Mahjong Soul free to play?

Yes. Mahjong Soul is free to download and play. It has gacha mechanics for cosmetic unlocks (character costumes, table designs) but the core game is fully accessible without paying.

What ruleset is most common online?

Internationally, Japanese Riichi Mahjong has become the most-played online ruleset, driven primarily by Tenhou and Mahjong Soul. Chinese Mahjong, Hong Kong Mahjong, and other variants have their own online communities but smaller English-language footprints.

Where can I learn to play Riichi Mahjong?

Daina Chiba’s “Riichi Book 1” is the standard English-language introduction. Mahjong Soul’s in-game tutorials cover the basics. YouTube channels dedicated to Riichi strategy expand from there. Our how to play Mahjong guide is a starting point.

The takeaway

Online Mahjong’s history splits into two streams: the four-player game’s transition from regional Japanese servers (Tenhou) to a global audience (Mahjong Soul), and the single-player Mahjong Solitaire’s quieter but constant presence on Windows desktops and browsers worldwide. Both are alive and well. For a different kind of single-tab distraction, the Chrome Dino game is one click away. For more on the four-player game’s rules and history, the Mahjong Wikipedia entry is a good starting point.

Related: Mahjong Solitaire Strategy: How to Win More Boards · The History of Cubefield · The History of The Impossible Quiz