Back-Rank Mate
How to spot it: check whether the enemy king's escape squares are all blocked by its own pawns. If so, an invasion on the open back rank (often after removing or deflecting the defender) is mate. And watch your own back rank: give your king luft (an escape) in time.
How to recognise it in a game
Check three things: the king is confined by its own pawns, an enemy rook or queen can enter the back rank, and the defender cannot capture or block. A loose back-rank defender is often the final tactical clue.
The common calculation mistake
A back-rank check is not always mate. Count every flight square, interposition and capture. Players also rush to make luft when a more urgent tactical threat is present, so compare the defensive move with the position's forcing moves.
How to defend against it
Create a safe escape square before the tactic becomes forcing, keep a rook connected to the back rank, or trade the attacking heavy pieces. The pawn move must not expose the king to a different diagonal or sacrifice.
Now spot it yourself
A real position: find the move. This is exactly what the drills in the app do, banded from beginner to expert.
How this lesson is made: this public explanation comes from the authored Strong Squares curriculum. Automated checks protect its chess data, source fields and learning flow. Independent chess-editor approval remains part of the private-preview release process. Read the teaching method.