2024/04/28 DPA: "Rook And Queen Choreography Dream"

White to move.

White is down a piece but has a passed e pawn that also controls the potentially important f6.

The d Rook controls the 6th rank and the h Rook contests the h file [although it's also en prise].

1. Rxh8 Kxh8  2. Qh6+ Kg8  3. Rd8+ Rf8  4. Rxf8#

Could it be that simple?  There was a recent puzzle with a similar Rook sac on h8 but it was the wrong idea due to the Black dark-squared Bishop that blocked our Qh5+ with Bh6.  Is there a better defense for Black?

1. ... Ng8 [to prevent 2. Qh6+; now 2. ... Kxh8 is a threat]  2. Rd8 Rf8 [if 2. ... Kxh8  3. Qh6#, as the Knight is pinned]  3. Rxf8 Kxf8  4. Qh6+ [again, the Knight is pinned so the Queen is safe] and White will skewer the King.

.

1. ... g5  2. Qxg5 Kxh8  3. Rd8+ Kh7  4. Qg8+ Kh6 - no, g8 is guarded by the Knight.

1. ... g5  2. Qxg5 Kxh8  3. Rh6+ Rh7  4. Qf6+ Kg8 and that fails also.

1. ... g5  2. Qxg5 Kxh8  3. Qh6+ Rh7 [note that, now that the g pawn is gone, ... Rg7 pinning the Queen is an option for Black]  4. Rd8+ Ng8 but now 5. Qf6+ allows 5. ... Qg7.

White does not want to allow Black to play ... Ng8 because that opens up the Black Queen to defend the 7th rank.

Could White  push e6 and then fork the K&Q on the 7th?

I couldn't see a better White move so I played 1. Rxh8 and was surprised when the response was 1. ... Kxh8 because I thought that 1. ... Ng8 and 1. ... g5 were more robust defenses [note:  I was wrong].

But now what?  2. Qh4+, Qh6+, and e6 look promising.

• 2. Qh6+ is the first reaction, since we are moving forward.  But after 2. ... Rh7  3. Qf8+ Ng8 and now the Black Queen is free
• 2. Qh4+ Kg7  3. Rd8, threatening 4. Qh8#, but 3. ... Rf8 holds
• 2. Qd4, threatening 3. e5^ attacking the Rook, is bad due to 2. ... Nc6
• 2. e6 forces Black to decide where to put his Rook
  • 2. ... Rf6  3. Qh6+ Kg8  4. Rd8+ Rf8  5. Rxf8#
  • 2. ... Rf8  3. Rd7 and Black can't both save the Queen and defend the Knight; 3. ... Qb8  4. Qh6+  5.Rxe7
  • 2. ... Rg7  3.
  • 2. ... Rh7  3. Qe5+

I can't find winning lines with Qh4+ or Qh6+ but I can with e6 so that probably is it [unless I've missed something with the other options].

OK, 2. e6 was correct.  Black played 2. ... Rg7.

3. Qh4+ Rh7 [if 3. ... Kg8  4. Rd8#]  4. Qf6+ [access to f6 is why White played 3. Qh4+ and not 3. Qh6+] Rg7  5. Rd7.

White will not only win the Knight but threaten checkmate due to the pinned Rook.  Black can prevent checkmate with 5. ... Qg8 but 6. Rxg7 Qxg7  7. Qd8+ Qg8  8. e7! and Black can only stop promotion by saccing his Queen.

I was wrong.  The puzzle solution will achieve checkmate much more quickly than mine.

However, I still saw the major themes and did the required visualizations so I'm satisfied with that.

I expect a lot of unhappy campers, though.

This was even more complicated than yesterday's [good on 'ya, chess.com!].

And like yesterday, there are many key points:

• The initial Rook exchange eliminates White's en prise Rook, draws the King to the open h file, and gives White future checking chances
• 2. e6 was the toughest move to find in my solution [I can't say about the puzzle solution since I didn't get it]:  it's a subtle move that forces Black to commit his Rook, either to the 7th rank or the f file and also threatens Rd7.   This then informs White's plans

• 3. Qh4+ and 4. Qd4+ was to pin the Rook

• 5. Rd8+ forced the Knight to g8 and it's no longer on the 7th rank

• 6. Rd7 attacks the Queen and the pinned Rook

I did not get the puzzle solution.

On the upside, I found all of the key ideas and used them to craft a solution that still wins, albeit more slowly.  I'll take that.

I figured out why White moved Qd4+ and not Qf6+ [which seems more logical since it gets closer to the enemy King]:  because ... Ng8 is not attacking the Queen on d4 whereas it is on f6.

.

And now the "puzzle is flawed" discussion.

The solution achieved 2 Qs v R+B, which is more advantageous than, for example, my solution, which was 2 Qs vs 1 Q or 1 Q vs no Q.

The puzzle eval was +M7; mine was +M27 at depth 44.

Yesterday's puzzle was more subtle in that there were 3 distinct checkmates of varying lengths whereas today's contained solutions of varying advantage.  So while you could argue that a -M2 or -M3 was just as good as the solution -M1 because all lines were forced, you might make the argument that because today's solution was optimal and there was only one [discounting repetitions], the other solutions are not valid even though they led to an overwhelming advantage.

This is an esoteric topic which I've already delved into fairly deeply yesterday so I don't feel like repeating it:  if you got the puzzle solution, you are one skilled solver.  If you got an alternate line which leads to a winning position, you are still hot stuff.  If you didn't get either, then you have some studying to do.

'Nuff said.