Welcome to IJCAI 2020 Mahjong AI Competition. In this competition, your task is to develop an intelligent Mahjong agent that is able to compete with other agents as well as human players on the online AI platform, Botzone. We adopt Mahjong Competition Rules (MCR) in this challenge. We provide a sample program for Mahjong beginers. You are also provided with our judge program which can help you learn the rules of MCR and debug your AI. The final winner after two formal rounds will be the champion of the competition.

Mahjong is a four-player imperfect information game that originated in China with a long history of more than 3000 years. In 1998 the All-China Sports Federation founded a universal competition standard called Mahjong Competition Rules (Guóbiāo Májiàng in Chinese pronunciation, literally Chinese Standard Mahjong), which we adopt in this competition. Mahjong involves strategy and a certain degree of luck, and the uncertainty brings to the game a lot of fun and challenge. Different from Mahjong’s varieties in Asia, e.g., Riichi Mahjong (Japan), Chinese Standard Mahjong encourages the players to adopt aggressive strategies, which makes the competition more watchable and attractive.

To write an expert-level bot, the participants may require analyzing the combinations of winning tiles that have different folds to get enough point hands, calculating the distance between current hand tiles and the final winning tiles to decide which tiles should be discarded. In order to successfully solve this challenge, participants can benefit from combining different areas of AI such as planning, game theory, heuristic search, MCTS, opponent modelling, and machine learning. Successfully integrating methods from these areas is one of the great challenges of AI.


  • Competition Registration
  • Conference Registration
    • The participants who advance to the finals will need to register for IJCAI-PRICAI 2020.
    • Each person can be a member of at most one team.
  • Click here to view the competition group page.

Get Started

Want to be stronger?

  • Learn Mahjong Competition Rules from our wiki
  • Download our judge program and Mahjong Helper to learn MCR in details
  • (Optional) We provide human player matches datasets: link, password: rm79 (P.S. if you are confused with the dataset, please contact us (botzone@126.com) with the confusing match's data)
  • Submit your AI and compete with each other!

Timeline (Tentative)

  • Registration Deadline: October 31th, 2020
  • Round 0 (Simulation Round): ~ October 31th, 2020
    • Simulation contests are planned every week, for participants to get familiar with the platform, game rules and contest rules
    • Scores in Round 0 will not be counted
  • Round 1 (Tournament Round): November 1st, 2020
    • Swiss-system tournament will be used
    • About three rounds will be held in this round, score in each round will be counted as 20%, 30% and 50% to the Round 1 score
    • Three rounds:
      • November 1st, 2020
      • November 8th, 2020
      • November 15th, 2020
    • Top 16 of the Round 1 will proceed to Round 2
    • Result of Round 1 will be announced on November 21st, 2020
  • Round 2 (Final Round): During IJCAI-PRICAI 2020 session
    • Swiss-system tournament will be used
    • Final result will be announced on IJCAI-PRICAI 2020 session

Paper Submission (Tentative)

  • Paper Submission Deadline: December 15th, 2020
  • Acceptance Notification: Janurary 1st, 2021
  • Camera Ready Deadline: During IJCAI-PRICAI 2020 session
  • Symposium: During IJCAI-PRICAI 2020 session
  • Submission:
    • Papers should be limited to 6 pages plus at most one additional page for references. Papers should include author names and affiliations.
    • Submissions should be formatted in PDF according to IJCAI guidelines and submitted by email to mahjongcompetition@pku.edu.cn.
    • Formatting guidelines and electronic templates are available on the IJCAI-PRICAI 2020 website.
  • Proceedings:
    • Accepted papers will be published on the botzone.org website. Authors will retain copyright and papers can be submitted elsewhere.
  • Symposium
    • Accepted papers will be presented during IJCAI 2020 Mahjong AI competition. At least one author of each accepted paper must register for the Mahjong competition and present the paper at the symposium.
    • The top 16 teams who advance the finals will be given the opportunity to briefly introduce their team, their agent, and the methods and strategies used. Posters are also be encouraged.


Wenxin Li
Professor at Peking University
Xiaotie Deng
Professor at Peking University
Zhihong Deng
Professor at Peking University
Guochuan Zhang
Professor at Zhejiang University
Yang Gao
Professor at Nanjing University
Wenlong Li
General Secretary at Mahjong International League
Weinan Zhang
Assistant Professor at Shanghai Jiao Tong University
Haifeng Zhang
Research fellow at University College London
Yutian Chen
Staff Research Scientist at Google DeepMind
LanZhou Zheng
CTO & Co-Founder at WEIZHIYU (Beijing) Technology co., LTd.


Our prior work on Mahjong AI and the platform Botzone:

  • Zhou, Haoyu, et al. "Botzone: an online multi-agent competitive platform for AI education." Proceedings of the 23rd Annual ACM Conference on Innovation and Technology in Computer Science Education. 2018.
  • Zhou, Haoyu, et al. "Botzone: a competitive and interactive platform for game ai education." Proceedings of the ACM Turing 50th Celebration Conference-China. 2017.
  • Zhang, Haifeng, et al. "Botzone: A game playing system for artificial intelligence education." Proceedings of the International Conference on Frontiers in Education: Computer Science and Computer Engineering (FECS). The Steering Committee of The World Congress in Computer Science, Computer Engineering and Applied Computing (WorldComp), 2012.
  • Li, Wenxin, et al. "Teaching AI Algorithms with Games Including Mahjong and FightTheLandlord on the Botzone Online Platform." Proceedings of the ACM Conference on Global Computing Education. 2019.



AI Lab, Institute of Network Computing and Information Systems, Department of Computer Science and Technology, School of Electronics Engineering and Computer Science, Peking University, is led by Professor Wenxin Li, AI Lab is dedicated to artificial intelligence in games, as well as computer education, biometric recognition and related fields.
WEIZHIYU (Beijing) Technology Co., Ltd. is a company focusing on artificial intelligence and application of games. With advanced game AI technology and leading industrial share, WEIZHIYU has long-term cooperation with many academic institutes, including Tsinghua University, Peking University, Chinese Academy of Science and Beijing Information Science & Technology University, for cutting-edge artificial intelligence research. The company has a technical team with over 30 people and the core members graduate from famous universities like Tsinghua University and Peking University.

Past Competitions

Competition Prizes
Rank Prize
1st USD 5,000
2nd - 16th USD 1,000

The rules we adopt in this mahjong competition is Mahjong Competition Rules.

click here to see wiki of mahjong game.
click here to download rules and sample code.
  • Timeline of this competition will be delayed, as IJCAI-PRICAI 2020 is postponed. Details will be revealed in the following days. 2020-05-08

    Click here to see how to use Botzone to join IJCAI 2020 Mahjong AI Competition. 2020-04-20

    IJCAI 2020 Mahjong AI Competition will be held as part of IJCAI 2020 in Yokohama, Japan, July 11-17, 2020. 2020-03-14

    Join the Wechat Group of Botzone. 2020-03-19

    Follow our Wechat Official Account for more information. 2020-03-14