1.
[{B:2R5/kpb1P1P/1p6/1P6/K7/8/8/8}
{V:White to play and mate in three. Try your solution on the board.;c8h8;
Correct;Incorrect.;The obvious move is 1 e8Q (or 1 g8Q), but Black replies 1...Bb8 and if White takes the bishop then Black is stalemated, while otherwise Black continues with 2...Ka8 and there is no mate. But now comes a typical piece of lateral thinking - if only White's queen and rook were the other way round on the eighth rank, then ...Bb8 wouldn't be a defense. How can White achieve this?}]

2.
[{B:2R5/kpb1P1P/1p6/1P6/K7/8/8/8}
If White promotes a pawn immediately by 1 e8Q or 1 g8Q, then Black replies 1...Bb8, and White cannot take the bishop because of stalemate, so there is no mate in two. The correct plan is to arrange for the rook to be on the other side of the queen, so that ...Bb8 is no longer an effective defense. However, 1 Rg8? (1 Rf8? is also met by 1...Bd6) fails to 1...Bd6 2 e8Q Bf8, blocking the back rank.]

3.
[{B:2R5/kpb1P1P/1p6/1P6/K7/8/8/8}
{S:c8h8}
The rook must go to the very end, so as to give White a choice of promotions. White doesn't threaten anything, because 2 e8Q and 2 g8Q would be met by ...Bd8, but Black's bishop cannot stay on c7. After 1...Bd6 White plays 2 g8Q, intending Qa8 mate, while if the bishop moves to any other square on the b8-h2 diagonal, White forces mate by 2 e8Q.]

4.
[{B:7R/kpb1P1P1/1p6/1P6/K7/8/8/8}
{S:c7d8}
1...Bd8. The best defense.
2 e8Q? and 2 g8Q? are met by 2...Kb8, while 2 exd8Q? is stalemate.]

5.
[{B:3b3R/kp2P1P1/1p6/1P6/K7/8/8/8}
{S:e7d8}{P:WBd8}
2  exd8B!   White avoids stalemate by underpromoting. Once again there is no threat, but Black's king is forced to move onto the dangerous back rank.   2...Kb8  3  Bxb6 mate.]
