2024/05/11 DPA: "e5 = Nexus"
White to move.
Black has dark square weaknesses but this time, he has a dark-squared Bishop for defense. One key will be how to get rid of that Bishop so White can threaten Qg7#.
1. Rxb2 Rxb2 2. Qd4 is great for White:
- 2. ... Qe5 3. Qxe5 Rxe5 4. Rxb8#
- 2. ... Re5 3. Rxb8+ and checkmate in 2 moves [2.... Re5 also fails to guard the b Rook]
Wait, these lines are wrong: White already gave up his b Rook so he can't play Rxb8. Classic problem of seeing a piece that's not there when trying to visualize.
1. Rxb2 Rxb2 2. Qd4 Qe5 3. Re1:
- 3. ... Qxd4 4. Rxe8#
- 3. ... Qh8 4. Rxe8#
- 3. ... Qxe1 4. Qg7#
- 3. ... Qe4+ 4. Rxe4 and # on g7 can't be stopped
- 3. ... Qh8
.
Critical to White's plan is the recognition that if White can play Re8 with no defense on the back rank, it's checkmate. 1. Rxb2 draws the b Rook away and 3. Re1 exposes the e Rook if the Queen moves off of the e file.
3. Re1 was the key move: if the Black Queen leaves the a1-h8 diagonal by capturing the Rook, White gets checkmate on g7. If the Black Queen leaves the e file by capturing the Queen, White gets checkmate on e8. Black cannot defend both except on e5, which is the intersection of these two lines of attack. But 3. Re1 forces the Black Queen to vacate e5. Very nice.
Another factor: White's King was not on the back rank so the potential 3. ... Qxe1 did not come with check.
My analogy to this dual threat: some dude is in a room with doors at both ends that have no locks. Zombies are closing in. He can bar either door but not both.
Zombies, 1; dude, 0.
.
Yes, Black could have accepted the loss of the Bishop and not recaptured...but then we wouldn't have a puzzle. As always, puzzles are not about optimal opponent responses but showcasing certain ideas [in this case, the Zombie Attack].
https://www.chess.com/blog/EnPassantFork/no-the-puzzle-is-not-wrong