On July 11, Tencent announced that its self-developed AI for chess games, LuckyJ, achieved the tenth dan rank on the renowned international mahjong gaming platform Tenhou, attaining a stable rank of 10.68. This achievement sets a new record for AI performance in the field of mahjong. Tenhou uses “stable rank” to measure chess players’ level of expertise, with top human chess players typically having an overall stable rank of 7.4. Currently, the top three mahjong AIs on Tenhou are LuckyJ, Suphx, and NAGA. Among them, LuckyJ reached the tenth dan rank after playing 1,321 games, while other AI players — Suphx, and NAGA — played 5,373 and 26,598 rounds respectively to reach this level, according to Tencent’s announcement. LuckyJ has also performed well in Guobiao Mahjong, a standardized mahjong game under the Chinese Official Mahjong rules. It has defeated six professional players in offline professional player invitation tournaments, becoming the first mahjong AI to triumph over top professional players in Guobiao Mahjong. [Tencent Announcement, in Chinese]