What is the fool's mate

The lion's mate, also known as the fool's mate, the beginner's mate, the fool's mate or the schoolboy's mate, is the shortest game of chess possible, it only lasts two moves. This part has above all an educational role: it shows the danger of arbitrarily pushing one's pawns. The push of the white pawn f opens the diagonal e1-h4, the white king being located at e1. As the push of the black e pawn opened the diagonal d8-h4 to the black queen, the latter can therefore move in one move to h4 where she defeats the white king.

The white camp is then obliged to cover this failure. In general, to cover a failure, a side has three possibilities:

capture the piece or pawn that defeated the king;
interpose a piece or a pawn between the piece which puts the king in check and the king (in the case of long-range pieces);
move the king to a position where he will no longer be in check.
Unfortunately,

the black queen cannot be captured;
no piece can come between the black queen and the white king, nor even a pawn since they have already advanced;
the king can only move in f2 where he would always be in check.
So this last move is the final blow: 2. ... Qh4 # (checkmate).

The joint thrust of the pawns located on columns g and f was fatal to White. In general, you have to be very careful on the push g2-g4 or g7-g5 for Black if the castling has not been done, because if the king is in the center, the diagonal h4-e1 or h5-e8 is weakened and, in the case of the small castling, this disrupts the structure of the pawns capable of protecting the king.

A four-move variant exists: 1. e4 f6 2. Qh5 + g6 3. Fe2 gxh5 ?? 4. Bxh5 #

The inversed fool's mate is the same position but in the other direction