Game 50. Nimzowitsch—A. Håkansson, Kristianstad, 1922. From a match; the first game in which appears my idea of a pawn sacrifice in the opening, not to obtain an attack, but merely, with gain of a tempo, to overprotect a strategical point with a view to cramping the enemy forces.

1. 4.Qg4 My innovation.
2. 10.Re1 White's plan is now clear. He has given up a pawn, careless when, if ever, he recover it provided his PK5 is maintained as an instrument to cramp Black's game. There is no idea of attack in 9. P-KR4, its object is solely to pave the way to the removal of some of the pressure on the PK5. The pawn sacrifice clearly comes within the category of sacrifice for the sake of blockade, cf. game No. 49.
3. 10…Bd7 B-B4 was essential here so as to leave the KB square free for the Kt to retreat to after P-R5.
4. 12.b4 White could, of course, have won the exchange here by 12. P-R5, Kt-K2; 13. Kt-Kt5, R-K1; 14. Kt-B7, R-Kt1; 15. Kt-Q6 ch; but with his undeveloped Q side and his unprotected PR5 he would have had some difficulties to contend with. The text move is the logical continuation.
5. 12…a6 Rather better was 12. ... K-Kt1; e.g., 13. P-QB3! P x P; 14. Kt x P, Kt x QKtP; 15. P x Kt, Q x Kt; 16. B-K3, Q x B; 17. B x P ch, K-B1; 18. KR-QB1 ch, B-B3; 19. P-Kt5!, Q x P; 20. Kt-Q4 with complications, which, of course, White, had he been so minded, could have avoided by simply playing 13. B-QKt2.
6. 17.Qg4 The Q is well placed here.
7. 18…Re8 His only move. It will be noted that the over-protector, the RK1, now has the QB file opened for him without any trouble to himself. In order to avoid loss of material Black has to submit to a curious regrouping of his forces.
8. 22…Qa8 The Q finds herself in a position to which as a rule she would only be consigned in a problem.
9. 27.Qxd7+ And mates next move.