1) Black's 4th move is 4...Re1+.
2) White plays the moves 1.f3, 2.Kf2, 3.Kg3, 4.Kh4. Black's 4th move is to give mate.
3) A game opens 1.a3. White's 5th move is to give mate with a rook.
Here are the solutions:
1) 1.e4 h5 2.Qxh5 Rxh5 3.e5 Rxe5+ 4.Kd1 Re1+.
2) 1.f3 e6 (1...e5 will also do) 2.Kf2 Qf6 3.Kg3 Qxf3! 4.Kh4 Be7 mate.
3) 1.a3 e5 2.Nc3 Bxa3! 3.Ne4 (Dia) 3...Bf8! 4.Ra5 Ke7! 5.Rxe5 mate.
For those who enjoy these puzzles I offer two more challenges. For a change I know (or think I know) the originator - American (ex Hungarian) GM Pal Benko - more known for his development of the Benko Gambit than for his endgame studies.
1) Black's 5th move is to promote a pawn to a bishop with mate.
2) Black's 5th move is to promote a pawn to a knight with mate.
The first is relatively simple and I suspect there may be more than one solution. At least I had forgotten the solution, and when I tried to reconstruct it, the solution I found seemed rather unfamiliar. The solution to the second task I find rather surprising and I suspect I would have had problems finding it without the hints I got from an impatient task giver.
