1.
[{B:b1B1Q3/pr6/k7/P6p/1P6/2P2q2/1K6/8}
{V:This is quite a tricky problem, but that should not put you off tackling it. Although it is given as a mate in eight, the play is more like that of an endgame study (indeed, the composer Rusinek is best known as a world-class study expert). The wonderful solution is certainly a worthwhile reward for those who do persevere. White to play and mate in eight. Try your move on the board.;c3c4;Correct;Incorrect.;It isn't giving too much away to say that the first move is 1 c4 (threatening mate on b5) and that Black responds by 1...Qf6+. Then White's immediate ambition is to avoid perpetual check. His method of doing this is spectacular and unexpected.}]

2.
[{B:b1B1Q3/pr6/k7/P6p/1P6/2P2q2/1K6/8}
White is a rook down, so his only hope of winning, let alone giving mate in eight, is to exploit the precarious position of Black's king. It is true that White can win Black's queen by 1 Qe5 Qd1 2 Qe6+ Kb5 3 Qe8+ Kc4 4 Be6+ Kd3 5 Qd8+, but this line certainly isn't going to lead to mate in eight. The above line is typical, however, in that White's attacking attempts don't lead to mate because Black's king slips out via b5. This is the basis for White's first move.]

3.
[{S:c3c4}
1 c4!
In addition to covering b5, this sets up the deadly threats of 2 Qb5 mate and 2 Qe6 (or g6)+. There is also a potential mate by Qc6, and it is obvious that Black's queen can't cover all these squares. It follows that Black's only hope is to try for perpetual check.]

4.
[{S:f3f6}
1...Qf6+
The best attempt 1...Qf2+ and 1...Qg2+ are both met by 2 Ka3!, when Black has nothing better than 2...Qf3+ transposing into the main line, but with White having saved a move.]

5.
[{S:b2a2}
2 Ka2!
Care is required. White's king would like to head towards a4, but 2 Ka3? allows a check on c3. We shall see in a moment why 2 Kb3? Qf3+ is bad.]

6.
[{S:f6f2}
2...Qf2+
The only chance, since the desperate 2...Qb6 is refuted by 3 axb6 Kxb6 4 Qe5 with mate in at most two more moves.]

7.
[{S:a2a3}
3 Ka3!]

8.
[{S:f2f3}
3...Qf3+
Certainly not 3...Qg3+? 4 Ka4 with a quick mate. Now, however, White appears to have arrived at a dead end since the obvious 4 Ka4 is met by 4...Qd1+ 5 Ka3 Qa1+ and the checks can't be avoided. Other king moves are met by ...Qf2+ and White is not making progress. If you have not found the whole solution, this is a good moment to stop and figure out what comes next.]

9.
[{S:e8e3}
4 Qe3!!
A truly incredible move. Already a rook down, White offers his queen with check. But if Black accepts, then 4...Qxe3+ 5 Ka4 leaves him in an impossible position. The threat is 6 b5 mate, and Black can only delay the end temporarily by 5...Qb3+ 6 Kxb3 h4 7 Ka4 h3 8 b5 mate. Therefore Black has to decline the sacrifice and move his queen away. However, Black has achieved some success. White's queen is not so actively placed on e3, and instead of threatening four different mates White's only threats are Qe6 and Qh6. Black can just about cover both squares. Incidentally, we can now see why 2 Kb3? Qf3+ would have been bad; the trick with Qe3 doesn't work when White's king is on b3, because Black simply ignores the offered queen and plays ...Qd1+.]

10.
[{S:f3f6}
4...Qf6
Not only preventing a queen mate, but also setting up a counter-threat of 5...Qa1+. Once again it is worth stopping to think about White's next move.]

11.
[{S:e3h6}
5 Qh6!!
The same idea again, but this time Black's queen is pinned, so he has no choice about accepting the queen sacrifice. If Black had played 4...Qc6, then White's reply would have been the same.]

12.
[{S:f6h6}
5...Qxh6
Now that Black has been deprived of his check on a1, the white king can close in for the kill.]

13.
[{S:a3a4}
6 Ka4]

14.
[{S:h6c6}
6...Qc6+
There is no defense to the deadly threat of b5 mate. Black can only delay the end by one move.]

15.
[{S:b4b5}
7 b5+]

16.
[{S:c6b5}
7...Qxb5+]

17.
[{S:c4b5}
8 cxb5 mate.]