Chess Online

What happens after 2. Kf1 ??

Because after 3. Kg2 Qf5, white can respond with:

4. Qd4! (threatening Qh7#)

The only way of dealing with the threat satisfactorily is to play 4... Be5 and now 5. Qd7+ forces a trade of queens, because Kh8 loses to 6. Qe8+ Kh7 7. Qg8# If you try to block with either the queen or the bishop at any point, they'll just be taken. So after the exchange of queens, you might try to generate counterplay by pushing 6... e3, but then 7. Bf5 threatens a discovery. You don't want to play 7... e2 to allow Rxb6+ followed by Rxb1, when white will have extinguished all your counterplay and be up a rook, so you have to move the king, and then 8. Bd3 protects the c-pawn and covers e2. You can't play an immediate Re1 in response because your bishop is also on the e-file, so 9. Re6 threatens the bishop and, when it moves, adds another attacker to the pawn. Materially, it's all equal, but white has the better position.

A better response to 2. Kf1 is 2... Qc4+. You don't want to block with the queen because an exchange can't be forced: your opponent will just play 3... Rb1+ and the queen, rook, and bishop will coordinate in a mating net.

Therefore, you have to move the king. If you play 3. Kg1, then:

3... Rb1+
4. Kg2 e3
5. Qf3 Qxc2+
6. Kh3 (because blocking with the queen is obviously futile) Qh2+
7. Kg4 e2

The pawn is protected on both ranks and will promote.

If you play 3. Kg2, then:

3... e3
4. Qe1 (threatening the rook if the queen moves) Qxc2+

Now, you don't want to put the king on the back rank, because Rb1 pins the queen, and you don't want to block with the queen for all the same obvious reasons, so Kh3 and Kf3 are your natural moves. Of these, I think 5. Kf3 is slightly more accurate because it keeps an eye on the e-pawn. Now 5... Qf5 appears to hang the rook, but you actually win the queen for the rook because 6. Qxb4 is met with the discovered check Bd6+ followed by Bxb4. White will play Kxe3 to get away from check, but the endgame is obviously won.

If 5. Kh3, then it works a bit like the 3. Kg1 line analyzed above:

5... Qh2+
6. Kg4 Bd6+
7. Qxb4 Bxb4

Except now the pawn can't be taken by the king, so more material has to be given up to grab it. For example:

8. Bf3 e2
9. Bxe2 Qxe2+

And now white's advantage is even more decisive than the rook for a queen exchange above.