2023/12/16 DPA: "Need A Chimney Sweep, Guvnor?"

Black has light square weaknesses and although he has a light-squared Bishop, it's not doing much defense on b7.

Black threatens M2 so White must checkmate first.

Black's back rank is vulnerable.

The first problem:  does White use d8 or e8 for the Queen check?

Since this is a puzzle, we know it matters so what are the pros and cons of each?

Given that Black's light squares are weak, it makes sense to use e8, a light square.  Also, it gives access to and support for the g6 square.

1. Qe8+:  Black can either block with the Rook or flee to h7.

I just noticed Black's Rook is hanging.

Also, don't forget about the potentially open h file.

If 1. ... Kh7, White lacks full control of g6; otherwise, Bg6 would be checkmate.

Taking the Rook is too slow since it doesn't come with check and Black has -M2 starting with a check.

2. Ng5+ is a way to open up the h file. 

2. ... hxg5  3. Bg6+ Rxg6  4. Rh1+ Rh6  5. Qxh8+ Kxh8  6. Rd8+ Kh7.  That doesn't quite work.

How about 5. Rxh6+:  if 5. ... gxh6  6. Qf7#

If 5. ... Kxh6  6. Rh1+ Kg5  7. Qh5+ Kf4  8. Rh4#

Time:  21 minutes

I just saw an error in my analysis:  6. ... Kg5 is impossible because the pawn is there [the one that captured the Knight].  So 6. Rh1 is checkmate.

[edit:  hat tip to @bryancfb, who pointed out that 7. Qh5+ is a blunder due to 7. ... Rxh5; I didn't "see" the other Rook in my visualization.]

Now I have to go back and calculate what happens after 1. ... Rf8.

2. Bf7+ [similar motif to 2 days ago] Kh7  3. Ng5+ hxg5  4. Rh1#

Since this is a shorter, less complicated checkmate, I think the solution will be the first variant.

Yeah, I was right.

This is a modified Chimney Mate where, instead of a Black piece being on g6 to complete the Chimney, White's Queen controlled that square.

Key ideas:

• Recognizing the -M1 required a check on every move
• Being able to open up a critical file
• Control of the light squares
• Correctly choosing which square for the Queen check
• Attraction trade [bringing the King forward further into the Chimney]
• Not worrying about material

One complaint is that the puzzle is so difficult, only a GM could solve it.  This is clearly not the case as plenty of people solved it and none of them are likely GMs.  There are many levels in between you and a GM.

And, even if it were the case, there are still things you can learn from the solution so even if you didn't solve it, you still understood parts of it and you can use that as a foundation upon which to build.