A relatively fascinating data-driven study shows how chess openings have changed in popularity over time.
One thing that jumps out at me is how much of an impact the “between wars” grandmasters like Alekhine and Capablanca had in the ’20s and ’30s. They played 1.d4 most of the time as White, eventually countering it with the unorthodox 1…Nf6 as Black (leading to “Indian” defenses and other hypermodern ideas). These were relatively radical ideas at the time. Now they’re classic, and fundamentally sound.
White’s first move:
Black’s first move:
Full study here.