Supposing White wants to try the immediate exchange on f6, hoping that somehow or other he will be able to take advantage of the weakness resulting on f6 and h6. In exchanging he can give up either his Knight d5 or his Bishop g5. In both cases there are promising possibilities for attack, but Black, with correct play, can sufficiently defend himself and even get the better.
If White plays (1) Ktxf6 he has to lose a move before he can bring up other pieces to help in the attack, for after Pxf6 he must first move the Bishop g5. The only good square for the Bishop is h4 from where he maintains the pin on f6 which would become very dangerous for Black if he could not prevent White's Queen from entering on h6 or render the double threat on f6 ineffective in some other way. The logical continuation for Black is to answer (2) B-h4 with K-h8 in order to occupy the g-file with his Rook as soon as possible. Indeed, this is at the same time the best defense against White's threat, for if White now plays (3) Q-d2; Black replies Ktxf3+; (4) Pxf3, Bxf3; and he is the first to take advantage of the open g-file as his King has already made room for the Rook.
It would be dangerous for Black to play (3) …, Bxf3 instead of Ktxf3. For White would continue (4) Q-h6 and the only way for Black to prevent the disaster threatened on f6 is to give back the piece he just won: (4) …, Kt-e2+; (5) K-h1, Bxg2+; (6) Kxg2, R4-g8+; (7) K-h1, R-g6; or (6) …, Kt-f4+; (7) K- h1, Kt- g6. In either case Black's defense is very difficult.
The play outlined in the last variation suggests a better method for White to institute the attack in the position of Diagram 47. This is the preparatory move (1) Q-d2. (1) Bxf6 is obviously not as good, as Black can soon drive away the Knight d5 by P-c6, relieving f6 of all pressure.
In answer to (1) Q-d2, which threatens (2) Bxf6, (3) Q-h6, (4)
Ktxf6 and (5) Qxh7 mate, Black has three replies, namely: Bxf3 or
Ktxf3 or P-c6.
That (1) …, Bxf3 is not sufficient can easily be seen. White continues (2) Bxf6, Q-d7; (3) Kt-e7+/-, and Black must give up the Queen for the Knight as (3) …, K-h8 would be followed by (4) Bxg7+, (5) Q-g5+ and (6) Q-f6 mate. It is interesting to note that it is just the one move which White is ahead in the development that gives him the win. If he tried to checkmate Black by (3) Q-g5, P-g6; (4) Q-h6 he would be checkmated himself by (4) …, Kt-e2+ followed by Bxg2+ and Q-g4+, etc.
(2) …, Pxf6 would not be of avail either. The consequence would be: (3) Q-h6, Kt-e2+; (4) K-h1, Bxg2+; (5) Kxg2, Kt-f4+; (6) Ktxf4, Pxf4; (7) K-h1, K-h8; (8) R-g1, R-g8; (9) Rxg8+, Qxg8; (10) R-g1 and the mate can only be averted by the sacrifice of the Queen for the Rook.
The second defense which Black could try is (1) …, Ktxf3+; (2) Pxf3, Bxf3. Now (3) Bxf6, Pxf6; (4) Q-h6 would be fatal for White as Black plays K-h8 and there is no protection against the threat R-g8+. But White can again make a preparatory move which secures for him the victory. This is (3) P-h3, with the view to make room for the Rook by K-h2. The only way to counter White's threat is now P-c6. However, after (4) Ktxf6+, Pxf6; (5) B-h4, K-h8; (6) K- h2, R-g8; (7) R-g1, Q-e7; (8) R-g3 Black is unable to stave off defeat any longer. Whatever he plays, White succeeds in attacking f6 for the second time while Black has no second protection at his disposal. For instance, (8) …, B-h5; (9) Q-h6, B-g6; (10) R-f3—or (8) …, Rxg3; (9) Pxg3 and (10) Rf1.
The most interesting line of defense is the third one mentioned, that is (1) …, P-c6. After (2) Ktxf6+, Pxf6; (3) B-h4 a situation arises similar to the one discussed in the line of play commencing with (1) Ktxf6+, but with the big difference that White is now one move ahead in the attack. This is the move Q-d2 in answer to which Black was forced to make the move P-c6 which does not improve the constellation of the Black pieces in any way.
This one move is sufficient to secure for White an easy victory. After (3) …, Bxf3; (4) Q-h6, Kt-e2+; (5) K-h1, Bxg2+; (6) Kxg2, Kt-f4+; (7) K-h1, Kt-g6 the position of Diagram 48 is reached in which White can force the mate, or win Black's Queen in a most ingenious manner. If White tried to win by (8) R-g1, threatening mate in four moves through Rxg6, Qxg6, Q-h6 and R-g1 Black could sufficiently defend himself with (8) …, P-d5, unpinning the Pawn f7 and enabling B-e7, which would supply the much needed protection for the square f6. However, White can frustrate Black's intention by playing (8) P-d4!! If Black takes with the Pawn, (9) P-e5 follows forcing Pd6xe5 after which Black cannot any more intercept the diagonal of the Bishop c4 so that there remains no defense against (10) R-g1.