This week, we feature another fine composition by the young Uri Avner, who was just 15 when he composed
this problem. Look out for the set play.
Set play:
1...Rxe4 2.Qg5#;
1...Bxe4 2.c4#.
Key: 1.Re1! Threat 2.Sf7 and giving a flight on d6. Now we have changed
mates after the two captures on e4:
1...Rxe4 2.Nc4#;
1...Bxe4 2.Rd5#.
In addition, we have three mates after the various captures on d6:
1...Rxd6 2.Qg5#;
1...Nxd6 2.c4#;
1...Kxd6 2.e5#.
Note that the set play mates 2.Qg5 and 2.c4 both reappear in the post-key phase.
This, combined with the new mates provided against the set play defences, makes the
problem a Rukhlis.