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? 

Google's AlphaZero surpassed the sum of human chess knowledge

Leela Chess Zero: AlphaZero for the PC

In Just 4 Hours, Google's AI Mastered All The Chess Knowledge in

AlphaZero: The AI from Google which mastered Chess in 4 hours

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

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

AlphaZero: Four Hours to World Class from a Standing Start

Deepmind's AlphaZero shows unprecedented growth in AI, masters 3

Google's self-learning AI AlphaZero masters chess in 4 hours

AlphaZero and the Beauty of the Artificial Mind

Google's AI became the world's best chess player in just four

Understanding AlphaZero Neural Network's SuperHuman Chess Ability

Move over AlphaGo: AlphaZero taught itself to play three different