Could someone explain this graph ( from Google Deep Mind - Alphazero article) : r/deepmind

Is DeepMind's AlphaGo Zero Really A Scientific Breakthrough?

Acquisition of chess knowledge in AlphaZero

A general reinforcement learning algorithm that masters chess

AlphaZero paper discussion (Mastering Go, Chess, and Shogi) • Life

David Silver, Google DeepMind: Deep Reinforcement Learning

AlphaZero implementation and tutorial, by Darin Straus

After AlphaGo Zero's Fabulous Win, What's DeepMind Been Upto?

Reinforcement learning is all you need, for next generation

AI Reveals New Possibilities in Matrix Multiplication

How to build your own AlphaZero AI using Python and Keras

Acquisition of chess knowledge in AlphaZero