What is AlphaZero?

AlphaZero is a self-learning computer programme from Google DeepMind that learns the board games Go, Chess and Shogi using its algorithm. For this it combines machine learning with neural networks. In order to learn one of the board games mentioned, the Artificial intelligence only the rules of the game, playing conditions and intensive playing against itself. It is not necessary to be taught by humans.

AlphaZero is based on the approach of AlphaGo Zerowhich was also developed by DeepMind.

How powerful is the programme?

Since AlphaZero is self-learning, its performance increases with every match played. It only knows the respective rules of the game and starts playing against itself with random moves. It evaluates its moves according to the result and thus learns which strategies work best.

After just 4 hours, AlphaZero was able to play chess at a superhuman level, surpassing the playing strength of world chess champion Magnus Carlsen with an Elo rating of over 2800. After 9 hours of training, it surpassed even the best chess programme up to then, Stockfish 8, with a calculated Elo rating of 3300.

After 34 hours AlphaZero has mastered the board games Chess, Shogi and Go and challenged all the leading programmes up to that point. Besides winning against Stockfisch 8 in chess, Elmo did it in shogi and AlphaGo defeated in Go.

It should be noted, however, that for the immense number of games against itself, very much computing power needed is. To make this possible, a large amount of TPUs (tensor processors to speed up machine learning applications) from Google were used. This allowed AlphaZero to complete approximately 44 million chess games in 9 hours, 24 million shogi games in 12 hours and 21 million Go games in 34 hours, putting AlphaZero's extremely rapid learning success into perspective.

Important games

AlphaZero and Stockfish

Stockfish is a chess programme, which, unlike AlphaZero, trained by humans became and as Open Source is available free of charge. Stockfish's algorithm uses a huge repertoire of moves, which it has learned by playing against human players. AlphaZero lacks this human influence, which is why the game is considered unconventional.

In 2017, Stockfish 8 was the best chess program and was clearly beaten by AlphaZero. This was to prove that a self-learning algorithm is superior to a human-trained algorithm.

2021 Stockfish 14 (the latest version) is again the number 1 chess programThis was made possible, among other things, by the cooperation with Leela Chess Zero and the use of neural networks.

AlphaZero and Leela Chess Zero

Leela Chess Zero (Lc0 for short) is a chess program, which can be used free of charge as open source, just like Stockfish. However, it was modelled on AlphaZero in its mode of operation. Leela Chess Zero is based on Leela Zero Go, which in turn is modelled on Alpha Go Zero. Accordingly, Lc0 uses its artificial intelligence combined with machine learning and neural networks to learn chess. Indeed, one of the main purposes for developing Leela Chess Zero is to validate the methodology of AlphaZero.

There is no official match of AlphaZero against Leela Chess Zero. For this, Lc0 regularly competes against Stockfish and is now at a similar level. In 2021, Lc0 was in 2nd place in the ranking of the best chess programs, behind Stockfish 14.

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