Early days
Computer mahjong appeared on Japanese home computers and consoles in the 1980s, and arcades carried mahjong games for years. Online play arrived in the late 1990s and 2000s, with Japanese and Taiwanese platforms leading the way.
Riichi online
Tenhou, launched in Japan in 2006, became the benchmark ranked riichi platform, with a demanding ranking system and records of millions of games. Mahjong Soul, launched in 2019, added anime-style characters and became popular internationally. Online play helped riichi spread worldwide by allowing players to learn without a local club.
American and Chinese apps
American Mah Jongg players can play online against people and computer opponents using the current card, a service that expanded rapidly during the COVID-19 pandemic. In mainland China, apps for local styles have enormous audiences.
Artificial intelligence
Mahjong is challenging for AI because it involves hidden information and luck. Research systems, including Microsoft's Suphx (2019), reached very high ranks on Tenhou, and AI analysis tools now help players review their games. For learners, these tools can show which discard a strong player would have chosen.
