Category 3 - Kinda stupid - here's a couple of samples (below). The first puzzle (black to move) is easy - queen to h6. Should the white queen block, take it and continue the black queen to h2 with support from the rook on h8 - I don't care that the black rook on b8 is threated - it's check and mate. So how does the computer see this puzzle solved? Rook to h2, which is taken by the king and THEN bring the second rook to h8 - sure it's "valid" but then again, so was mine - without sacrificing a piece.
The thing is. 1..Qh6 doesn't work at all if white just plays 2 h3. Black is losing.
But there is no defense to 1.. Rxh2+. It is a forced mate.
/ Your rating is still below 1000. Things get much more interesting when you get your rating a bit higher.
As a newbie (playing for about four months) I use the Chess.com Puzzles (blue icon) almost daily. I would subscribe to unlimited puzzles BUT I find that the puzzles fall into one of four categories - each roughly 25% of the many thousands of puzzles I've solved:
Category 1 - Instructive and insightful. Demonstrate subtle but important chess strategies.
Category 2 - Overly Simple - I totally get it - back-rank mates are super! But better opponents RARELY leave the back door wide opened. Why so many back-rank puzzles?
Category 3 - Kinda stupid - here's a couple of samples (below). The first puzzle (black to move) is easy - queen to h6. Should the white queen block, take it and continue the black queen to h2 with support from the rook on h8 - I don't care that the black rook on b8 is threated - it's check and mate. So how does the computer see this puzzle solved? Rook to h2, which is taken by the king and THEN bring the second rook to h8 - sure it's "valid" but then again, so was mine - without sacrificing a piece. The second idiot puzzle, black to move, shows the rook on a8 under pressure from the rook on a1 - sure I could take the white rook but since the white queen is right next door why trade rooks for no strategic advantage??? So I move the a8 rook to b8 - ERROR! Why? The right way to play this is knight to b6, then bishop to g4. Depending if the white knight moves or not it's mate in two or three - BUT again the puzzle gods don't see this.
Category 4. Just dead wrong. This happens occasionally when moving a knight - often the correct move is obvious BUT the puzzle says it's incorrect. So then you try EVERY legal move with the knight and the puzzle says they are ALL wrong. SO press the "hint" again and the knight is highlighted - press "move" and you guessed it - the puzzle moves the knight to the first square you tried - FRUSTRATING!
I wish there were a better puzzle site - anyone know of one?