'Game Changer' PGN

Continuing with AlphaZero's Zeros (July 2019), about Sadler & Regan's book 'Game Changer', digging deeper into the book requires the corresponding PGN file. In Chapter 2, titled 'ZeroZeroZero', Sadler wrote,

At the beginning of 2018, I was invited to the DeepMind offices at St Pancras in London to study 210 games from the newest series of matches between Stockfish and AlphaZero. [...] I was provided with two files: a file of 110 games played without an opening book from the starting position, and a file of 100 games starting from various pre-determined opening positions (the positions used in the 2016 TCEC World Championship). The games in each file were grouped by colour so that I first played through AlphaZero’s Black games, and then its White games.

Last December, DeepMind released two files:-

• alphazero_vs_stockfish.pgn
• alphazero_vs_stockfish_tcec_positions.pgn

The game counts in each file match the numbers that Sadler gives, meaning that we're probably looking at the same files. Maybe I should say, 'almost the same files', because the two AZ_vs_SF PGN files are not grouped by color as Sadler describes. Where Sadler gives a game number, I also noticed differences.

Another PGN resource is available from newinchess.com (NIC). The product page, Game Changer: AlphaZero's Groundbreaking Chess Strategies and the Promise of AI, says, 'You can download all the games from the book as a PGN-file.' Although the first game in the book -- Kaissa - Chaos, World Computer Championship, Stockholm 1974 -- is missing from the NIC file, the next games in the book match the file. As a bonus, the 'Annotator' tags in the NIC file, e.g.:-

[Annotator "17293012532641473451"]

match the 'Round' tags in the AZ_vs_SF files, e.g.:-

[Round "17293012532641473451"]

This provides a cross-reference between the two sets of files. I'll use these files for further explorations.