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 says it built a 'superhuman' game-playing AI. Is it truly

CB article on AlphaZero suggests AlphaZero is playing a different

DeepMind's AlphaZero AI is the new champion in chess, shogi, and Go

Diversifying AI: DeepMind Pushes AI Toward Creative Game Players

Google's AI mastered chess in 4 hours

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

Is AlphaZero really a scientific breakthrough in AI?

AlphaZero - Chess Engines

Google's AlphaZero Destroys Stockfish In 100-Game Match

AlphaZero Chess: How It Works, What Sets It Apart, and What It Can

Google DeepMind's 'superhuman' AlphaZero computer taught ITSELF to