1.
[
{F:B}{B:K7/2q2n2/3n2kB/6P1/5P2/6P1/7b/8 BLACK}
{V:Black to move, helpmate in three. Try it on the board.;f7e5;Correct;Incorrect.;If only h7 were blocked and the knight on d6 moved away, then White could mate by g4 and f5. At first sight, the problem can be solved by playing the knight on d6 to h7, but after 1...Ne4 2 g4 Nf6 White has no pass move and is forced to destroy the mate by moving the bishop. The solution is to find a way of blocking h7 with a different black piece, in such a way as to give White a waiting move.}]

2.
[
{F:B}{B:K7/2q2n2/3n2kB/6P1/5P2/6P1/7b/8}
This problem is a study in tempo-play. White would like to mate by g4 and f5, but for this the knight on d6 has to move away and the square h7 must be blocked. The natural idea is to combine both of these in a single plan, by transferring the d6-knight to h7. This fails because after 1...Ne4 2 g4 Nf6 White is forced to move the bishop, and this disrupts the mating net. White will always require a waiting move, and this can only be with the king. It follows that Black's queen will have to move, and so the second idea is to use the queen to block h7. Of course, we mustn't forget about moving the knight on d6, but it is possible to combine both plans by moving the knight on f7, playing ...Qh7, and then playing the knight on d6 to f7. The only problem is that 1...Nh8 2 g4 Qh7 3 Kb8 Ndf7 pins the pawn on f4, and so White cannot deliver mate. This explains why the f7-knight must choose the right destination on the first move...]

3.
[
{S:f7e5}
1...Ne5
All the other pieces are going to move off the h2-b8 diagonal, so Black must prepare to unpin the f4-pawn.]

4.
[
{S:g3g4}
2.g4]

5.
[
{S:c7h7}
2...Qh7]

6.
[
{S:a8b8}
3 Kb8]

7.
[
{S:e5f7}
3...Nf7]

8.
[
{S:f4f5}
4 f5  mate.]
