How did Google's AlphaZero beat the world's best chess computer?

Google’s AlphaZero, after just four hours of training, last week trounced the highest rated chess engine in the world, Stockfish. How did it do this? 

Four hours after being taught the rules of chess, AlphaZero became

Google's AI Alpha Zero Beats Stockfish, The World's Strongest

Alphazero :: Computer-bridge1

Chess's New Best Player Is A Fearless, Swashbuckling Algorithm

Google AI Achieves Alien Superhuman Mastery of Chess and Go in

Google's AlphaZero Destroys Stockfish In 100-Game Match

AlphaZero: Four Hours to World Class from a Standing Start

AlphaZero on Carlsen-Caruana Games 1-8

Checkmate: how we mastered the AlphaZero cover, Science

Google's AI mastered chess in 4 hours

AI that defeated humans and changed the way chess is played is

Chess's New Best Player Is A Fearless, Swashbuckling Algorithm

Google's New AI Is a Master of Games, but How Does It Compare to

From Zero to Master in Hours: AlphaZero Accelerates Reinforcement