Microsoft AI attains top rank in Japan Mahjong platform

AI Super Phoenix well-suited for finance: Microsoft Japan chief tech officer

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Japanese Mahjong (Flickr - yui*)

Japanese Mahjong (Flickr - yui*)

TAIPEI (Taiwan News) – Microsoft Research Asia is publishing a paper on Super Phoenix, its Japanese Mahjong-playing Artificial Intelligence (AI), which has received the highest win rate on Tenhou (天鳳), an online Japanese Mahjong platform, Business Next reports.

Super Phoenix is the first AI playing on Tenhou to receive the 10th dan, a rank held only by 0.0054 percent of the human players, after 5,000 games in three months. Its average score per game is 8.7, while human 10th-dan players average only 7.5.

Google’s AlphaGo defeated human player Lee Sedol (李世乭) at Go in 2016, marking the total victory of AI in the field of strategic games with perfect information. Since then, developers have begun to focus on games involving imperfect information and chance, such as Poker, Mahjong, and StarCraft.

Libratus, an AI developed by Carnegie Mellon University, won US$1.77 million worth from four professional Texas hold 'em poker players in 2017, conquering the field of imperfect information games. However, according to Microsoft's calculations, there are 1048 kinds of concealed information at play in Japanese Mahjong compared to Texas hold 'em's 1,000.

The Super Phoenix teaches itself Japanese Mahjong strategy by sifting through the massive amount of game data on Tenhou. It has not only figured out how to play efficiently and aggressively, but it has also learned when to give up and turn defensive when it has an unlucky hand and even when to strategically attack third or fourth-place players to avoid losing more points when taking on the first place player is too risky.

Akira Sakakibara (榊原彰), chief technology officer at Microsoft Japan, said the technology developed in Mahjong AI could probably be used in the finance field. He said that the financial market is similar to a Mahjong game, as participants all need to optimize their returns and risks based on imperfect information and estimation of concealed information.

Tenhou has allowed other AIs to participate in the game before, but none but Super Phoenix has reached the rank of 10th dan. Nevertheless, Microsoft is unsatisfied with the result and is currently negotiating with the game developer to allow Super Phoenix to gain Tenhou-i, the hidden highest rank in the game, which has been attained by only 13 human players so far.