José Raúl Capablanca,
Chess fundamentals — Part I, Chapter II.10…
(1921)
“ Example 23.—In this position White's best line of defence consists in keeping his Pawn where it stands at R 2. As soon as the Pawn is advanced it becomes easier for Black to win. On the other hand, Black's plan to win (supposing that White does not advance his Pawn) may be divided into three parts. ”
