You got it 100%, classic decoy tactic. A queen and king (or rook and king) can always force checkmate against a lone king, so the puzzle is over cause you already reached a winning position and most players would just resign if they had white in that position. Every once in a while the player with the queen can screw it up, but it's a pretty easy win.
Melllvar1
Freyja33
GenshiV
Black rook to take pawn, white king takes rook, then you take their rook and it's king vs pawn promotion + king?
GenshiV
I mean I'm not sure what the end goal is, but that would secure a win eventually. No way a king, alone, wins against that.
QuanfaKibitzer
Thank you.
Freyja33
You got it 100%, classic decoy tactic. A queen and king (or rook and king) can always force checkmate against a lone king, so the puzzle is over cause you already reached a winning position and most players would just resign if they had white in that position. Every once in a while the player with the queen can screw it up, but it's a pretty easy win.