2024/06/09 DPA: "Back Rank Serenade Shuffle"

White to move.

Black's King is somewhat cramped but he still has h8.

Black's back rank is well-defended.

White would like to attack g7 but not only does Black have the dark-squared Bishop for defense, White does not have one for attack.  That means dark square attack will have to come from the other pieces [except the light-squared Bishop].

1. h5 is a possibility, especially if White can get rid of Black's liight-squared Bishop and take control of the b2-h7 diagonal.  But if Black ignores it and plays 1. ... Rb8, for example, his light-squared Bishop still guards g6.

2. hxg6+ Bxg6  3. Rxh6+ Kxh6  4. Rh1+ Bh5  5. Rxh5#

So 1. ... Rb8 is bad.  So 1. ... gxh5 maybe?  2. Rxh5, which gives Black a tempo.

Better is 1. ... g5, which closes the h file, which White does not want.

1. Ng5+ hxg5  2. hxg5^# [discovered check and checkmate].

Can Black decline the sac?  1. ... Kh8  2. Qxg7+ Kxg7  3. Rf7+ Kh8  4. Rh7#

Wait, that's not correct:  3. ... Kg8 and now 4. Rh7^ Kf8  5. Rf1+ Bf5.

5. Ne6+ [blocks the Bishop] Kg8

4. Rb7^ Kf8  5. Nh7+ Ke8  6. Bf7#.

The problem is that 4. Rc7^ accomplishes the same thing and since the puzzle cannot have 2, identical length solutions, one or both of them is wrong.

One thing I see is that when the Rook moves to discover the Bishop check, Black can block with 4. ... Bd5.  So one way to neutralize this is to play 4. Rd7 to prevent the Black Rook from supporting d5.  Now it's irrelevant whether Black plays it since the outcome doesn't change.

But now this creates another problem:  4. ... Kf8  5. Nh7+ Ke8 now attacks the Rook so White doesn't have time for 6. Bf7#.

6. Nf6+ [protecting the Rook] Kf8  7. Rf7#.

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There were several keys:

• Seeing how the Knight was poisoned after 1. Ng5+ due to hxg5  2. hxg5^#, which allowed it to get into fantastic attacking position
• Recognizing the Queen sac was the only way to force a win
• Noting that moving the Knight opened up the f file for the Rook
• Correctly calculating that Black's response would be 3. ... Kg8 and not 3. ... Kh8
• Anticipating the potential block of the Bishop discovered check with 4. ... Bd5 with the d Rook's support [yellow] and countering it a priori with 4. Rd7 [green]
• Keeping the Rook on the 7th rank to prevent the King from escaping
• Seeing 5. Nh7+
  • not easy to see a Knight check so far in the corner
  • it also might appear White is allow the King to escape to open waters

• 6. Nf6 [dark blue] was a killer move, checking Black AND protecting the Rook and forcing the King back to f8 where checkmate was delivered with the Rook [green] as it's protected by the Bishop [red] and the Knight covers e8 and g8

In yesterday's blog, I brought up that the final ... Rf3# move might have been difficult to see since we had just moved that piece to h3.  Today's puzzle is another example:  we had just moved the Knight to h7 so the bias might be against moving it again, at least so soon.

However, the Knight was needed on h7 to drive the King off of f8 to e8.  That task accomplished, the Knight can [and must] be redeployed.

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One thing that helped me is that I've seen this checkmate pattern before.  So while I didn't spot it early on, I did recognize it after I had found 6. Nf6+.

In general, I recommend trying to mimic my method of solving everything up-front before making the first move [maybe don't start practicing on a Sunday; try Monday first].  In this case, I visualized/calculated the entire 7 move sequence but it came incrementally:  I had to make a few mistakes in my calculations before I got the solution.  But this visualization will help you tremendously in a game.