Is my chess engine broken?

That was my first reaction. (I don't use engines).

I've been staring at that board for a few minutes to figure out why that is the move and I THINK I figured it out, so correct me if I'm wrong.

You sacrifice the Rook at c6, it is taken by the pawn from b7 to c6. your pawn on d5 recaptures the pawn on c6 threatening the Knight, the Knight moves to I think b6 threatening your Queen, you take with your Bishop from e3 to b6 and the Queen takes your bishop on b6 you then push the pawn to c7 and... checkmate. Discovered check and the pawn covers the only escape square.

There are a number of different lines, but they ALL look pretty nice (for White!) to me.

I haven't bothered to check with an engine (I don't own one anyway) so of course I could be wrong... but my first impulse was Rc6.

And there's no solution and explanation to the puzzles?

If I had a puzzle book like that, I'd throw it out.

I was looking more at

What happens if (instead of Qb5) black plays Kf8?

5. Bxa8 Qcx7 and black looks OK.

LOL.

I didn't copy the diagram correctly. Check the original post on page 1.

The Bishop should be on f8. Your comment is correct regarding my post (with the Bishop incorrectly shown on g7), but not for the actual position.

I wasn't checking with an engine either, which is evident by the fact I messed up the calculation.

I was showing this problem to my son when I realised the pawn was in the way. So the Knight goes to C5 threatening the Queen not B6. Bishop takes Knight and Queen takes Bishop at C5. Pawn pushes up to C7, Queen blocks and is then taken by your Queen and it's Checkmate.

... Queen blocks on b5, where it is defended by the a6 Pawn... but White's reply Bc6+ is the rock that tears the bottom out of Black's boat.

See post #25

I am amused by ... Qb5, Qxb5 axb5, Bc6#.

It seems cuter than ... Qb5, Bc6+ Qxc6, Qxc6#

Yeah, but I like the way that the White Queen on a4 guards the White Bishop on c6 THROUGH the Black Queen on b5.

Okay, I think everyone has missed the reason for this post.

Rc6 is already known to be the best move, this is from a puzzle book written by a 2700 GM, the puzzle comes with massive analysis and lines and has already been computer checked.

I posted this not to analyze this position, this message is because I am concerned that my engine is broken and is not analyzing correctly, and I wish to test my engine to make sure it can solve difficult tactics.

My engine is giving Rb6 as the main line now, which is just weird.

I would appreciate if people could post other complicated positions with known solutions so I can test my engine and see if it is defective.

I do not wish to share the name of the engine I am using because I do not wish to harm anyone's reputation.

The engine doesn't calculate masterious sacrifices well or certain types of winning endgames it doesn't really analyze the end position very well either that's why I usually analyze without engine unless it is one of those insane defensive moves or random queen moves that almost nobody would find

Like you can trick an engine in a drawn opposite color Bishop endgame occasionally

my chessbase stockfish 16.1 says Rc6

stockfish rb5

mine says king E2!!

After Rc8 Qxa6 is winning

what does your engine say