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Grandmaster level in StarCraft II using multi-agent reinforcement learning


Many real-world applications require artificial agents to compete and coordinate with other agents in complex environments. As a stepping stone to this goal, the domain of StarCraft has emerged as an important challenge for artificial intelligence research, owing to its iconic and enduring status among the most difficult professional esports and its relevance to the real world in terms of its raw complexity and multi-agent challenges. Over the course of a decade and numerous competitions1,2,3, the strongest agents have simplified important aspects of the game, utilized superhuman capabilities, or employed hand-crafted sub-systems4. Despite these advantages, no previous agent has come close to matching the overall skill of top StarCraft players. We chose to address the challenge of StarCraft using general-purpose learning methods that are in principle applicable to other complex domains: a multi-agent reinforcement learning algorithm that uses data from both human and agent games within a diverse league of continually adapting strategies and counter-strategies, each represented by deep neural networks5,6. We evaluated our agent, AlphaStar, in the full game of StarCraft II, through a series of online games against human players. AlphaStar was rated at Grandmaster level for all three StarCraft races and above 99.8% of officially ranked human players.

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Fig. 1: Training setup.
Fig. 2: Results.
Fig. 3: Ablations for key components of AlphaStar.
Fig. 4: AlphaStar training progression.

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Data availability

All the games that AlphaStar played online can be found in the file ‘’ in the Supplementary Data, and the raw data from the experiment can be found in ‘bnet.json’ in the Supplementary Data.

Code availability

The StarCraft II environment was open sourced in 2017 by Blizzard and DeepMind7. All the human replays used for imitation learning can be found at The pseudocode for the supervised learning, reinforcement learning, and multi-agent learning components of AlphaStar can be found in the file ‘’ in the Supplementary Data. All the neural architecture details and hyper-parameters can be found in the file ‘detailed-architecture.txt’ in the Supplementary Data.


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We thank Blizzard for creating StarCraft and for their continued support of the research environment, and for enabling AlphaStar to participate in In particular, we thank A. Hudelson, C. Lee, K. Calderone, and T. Morten. We also thank StarCraft II professional players G. ‘MaNa’ Komincz and D. ‘Kelazhur’ Schwimer for their StarCraft expertise and advice. We thank A. Cain, A. Razavi, D. Toyama, D. Balduzzi, D. Fritz, E. Aygün, F. Strub, G. Ostrovski, G. Alain, H. Tang, J. Sanchez, J. Fildes, J. Schrittwieser, J. Novosad, K. Simonyan, K. Kurach, P. Hamel, R. Barreira, S. Reed, S. Bartunov, S. Mourad, S. Gaffney, T. Hubert, the team that created PySC2 and the whole DeepMind Team, with special thanks to the research platform team, comms and events teams, for their support, ideas, and encouragement.

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Authors and Affiliations



O.V., I.B., W.M.C., M.M., A.D., J.C., D.H.C., R.P., T.E., P.G., J.O., D. Horgan, M.K., I.D., A.H., L.S., T.C., J.P.A., C.A., and D.S. contributed equally. O.V., I.B., W.M.C., M.M., A.D., J.C., D.H.C., R.P., T.E., P.G., J.O., D. Horgan, M.K., I.D., A.H., L.S., T.C., J.P.A., C.A., R.L., M.J., V.D., Y.S., A.S.V., D.B., T.L.P., C.G., Z.W., T. Pfaff, T. Pohlen, Y.W., and D.S. designed and built AlphaStar with advice from T.S. and T.L. J.M. and R.R. contributed to software engineering. D.W. and D.Y. provided expertise in the StarCraft II domain. K.K., D. Hassabis, K.M., O.S., and C.A. managed the project. D.S., W.M.C., O.V., J.O., I.B., and D.H.C. wrote the paper with contributions from M.M., J.C., D. Horgan, L.S., R.L., T.C., T.S., and T.L. O.V. and D.S. led the team.

Corresponding authors

Correspondence to Oriol Vinyals or David Silver.

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Competing interests

M.J., W.M.C., O.V., and D.S. have filed provisional patent application 62/796,567 about the contents of this manuscript. The remaining authors declare no competing interests.

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Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Peer review information Nature thanks Dave Churchill, Santiago Ontanon and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

Extended data figures and tables

Extended Data Fig. 1 APM limits.

Top, win probability of AlphaStar Supervised against itself, when applying various agent action rate limits. Our limit does not affect supervised performance and is acceptable when compared to humans. Bottom, distributions of APMs of AlphaStar Final (blue) and humans (red) during games on Dashed lines show mean values.

Extended Data Fig. 2 Delays.

Left, distribution of delays between when the game generates an observation and when the game executes the corresponding agent action. Right, distribution of how long agents request to wait without observing between observations.

Extended Data Fig. 3 Overview of the architecture of AlphaStar.

A detailed description is provided in the Supplementary Data, Detailed Architecture.

Extended Data Fig. 4 Distribution of units built in a game.

Units built by Protoss AlphaStar Supervised (left) and AlphaStar Final (right) over multiple self-play games. AlphaStar Supervised can build every unit.

Extended Data Fig. 5 A more detailed analysis of multi-agent ablations from Fig. 3c, d.

PFSP-based training outperforms FSP under all measures considered: it has a stronger population measured by relative population performance, provides a less exploitable solution, and has better final agent performance against the corresponding league.

Extended Data Fig. 6 Training infrastructure.

Diagram of the training setup for the entire league.

Extended Data Fig. 7 performance details.

Top, visualization of all the matches played by AlphaStar Final (right) and matches against opponents above 4,500 MMR of AlphaStar Mid (left). Each Gaussian represents an opponent MMR (with uncertainty): AlphaStar won against opponents shown in green and lost to those shown in red. Blue is our MMR estimate, and black is the MMR reported by StarCraft II. The orange background is the Grandmaster league range. Bottom, win probability versus gap in MMR. The shaded grey region shows MMR model predictions when players’ uncertainty is varied. The red and blue line are empirical win rates for players above 6,000 MMR and AlphaStar Final, respectively. Both human and AlphaStar win rates closely follow the MMR model.

Extended Data Fig. 8 Payoff matrix (limited to only Protoss versus Protoss games for simplicity) split into agent types of the league.

Blue means a row agent wins, red loses, and white draws. The main agents behave transitively: the more recent agents win consistently against older main agents and exploiters. Interactions between exploiters are highly non-transitive: across the full payoff, there are around 3,000,000 rock–paper–scissor cycles (with requirement of at least 70% win rates to form a cycle) that involve at least one exploiter, and around 200 that involve only main agents.

Extended Data Table 1 Agent input space
Extended Data Table 2 Agent action space

Supplementary information

Reporting Summary

Supplementary Data

This zipped file contains the pseudocode, StarCraft II replay files, detailed neural network architecture and raw data from the experiment.

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Vinyals, O., Babuschkin, I., Czarnecki, W.M. et al. Grandmaster level in StarCraft II using multi-agent reinforcement learning. Nature 575, 350–354 (2019).

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