Using Packed Circle's to Visualise Chess Openings

Using the 135 chess games played during the 80s and 90s by Garry Kasparov and Anatoly Karpov, this uses one of D3's packing algorithms to show the nested opening lines (first five moves or ten-ply). The size of the circles reflects the number of games contained within that line of play. So we can see that Kasparov's favourite opening move as white, over all the games, is d4, queen's pawn, but that he often chose e4, king's pawn, variants. Karpov shows less variety in his opening lines, with d4 much favoured.
By clicking on one of the buttons below one can select a time-ordered range of the games. Selecting the upper-third range shows that Kasparov switch exclusively to a d4 opening move, as did Karpov, with the exception of two Nf3 (king's side knight) openings.

Kasparov White

Karpov White