To Viktor Volkov, who taught us that even a database of millions can hide a single truth.

ChessBase has improved its automated "duplicate deletion" system. The 2023 release has cleaned up errors from previous versions, ensuring that you aren't studying a game where the move order was misrecorded.

Viktor never returned to competitive chess. Instead, he wrote a single line of code: a filter that flagged ghost games by statistical entropy. He donated it to ChessBase for free. In the acknowledgments of the 2025 edition, under “Special Thanks,” a single line appeared:

A common question: "Why pay for ChessBase Mega when Lichess has a free database of 4 million games?"