Chessical: This is an extremely valuable game. Keres shows how to play the Black side of the Chigorin defence to the Ruy Lopez. I enclose a few excerpts from Keres' notes to the opening moves of this game.
<16…Be6!> The whole variation, with the exception of Black's last move, has already been encountered a hundred times in tournament practice, and over the course of the last twenty five years it has been considered unfavourable for Black. However the move in the game, which, incidentally, occurred to me during preparation for an encounter at the Olympiad in Tel Aviv, casts fundamental doubt on the correctness of this categorical assessment.
<17 a3> Undoubtedly one of the best retorts to the system chosen by Black. Obviously the advance 17 d5 achieves nothing because of 17 ... Nb4; if now <18. Rcl>, then Black has the possibility of 18 ... Nxa2! 19 dxe6 Nxc1 20 Qxc1 Rac8, and White must lose a piece.
<18 ...Rac8> has to be tested, so as only after 19 Bd3 to retreat the queen to b8. But it seems to me that it is better to leave the rook on a8 for a while in order to support the a-pawn. For the time being the concession of the c-file to the opponent has no real significance.
<19.Bd5> Without sufficient practical experience it is difficult to recommend how White best continues here. Gligonc's attempt to exert pressure on the b5 pawn seems quite logical but it does not lead to the desired result.
<20.d5> After this Black has an excellent position, but also the continuation 20 axb4 Qxb4 need hardly be feared. It looks like Black has come out of the opening with a quite satisfactory position.