and wins and lost percentage also seem to not be rightly displayed - if you will compare the summary of games displayed after the move chosen and displayed before sometimes it's not correct at all. hope i'm clear with this explanation :) gl
Book Openings

Im also interested in this question. It doesnt appear to be based on views- some openings have comments but 0 popularity. I doubt its based on chess.com games, although that could always be the case...

Good question. "English Opening / Great Snake Variation" is 10x as popular as the Slav/Semi-Slav... of course that's silly. I'm guessing # of page views.

I found these most played stats at another well known site with a DB of about 500,000 games. So, I am still wondering what our Book Openings "Popularity" numbers mean.........??
- A04 - Reti Opening (8,125 games played)
- B22 - Sicilian, Alapin (6,962)
- B06 - Robatsch (6,621)
- B90 - Sicilian, Najdorf (5,841)
- A07 - King's Indian Attack (5,676)
- A46 - Queen's Pawn Game (5,674)
- A15 - English (5,254)
- B40 - Sicilian Kan (5,223)
- A45 - Queen's Pawn Game (4,500)
- B01 - Scandinavian (4,436)
- B33 - Sicilian (4,377)
- B07 - Pirc (4,347)
- E12 - Queen's Indian (4,327)
- D02 - Queen's Pawn Game (4,312)
- B23 - Sicilian, Closed (4,229)
- A00 - Uncommon Opening (4,175)
- C42 - Petrov Defense (4,164)
- E15 - Queen's Indian (4,078)
- B30 - Sicilian (4,060)
- D37 - Queen's Gambit Declined (3,871)
In the Learn>Book Openings what are the "Popularity" numbers based on? Doesn't seem to be the number of games in the DB.