White to move. Find the one move that wins. About 900 ELO.
One knight jump attacks the king and the queen.
Find a knight check that hits another big piece at the same time.
One piece attacks two or more enemy pieces at once. Your opponent can only save one.
Find two loose or valuable pieces that one of your pieces could reach from the same square. Knights and queens fork best.
Knights fork best when two targets sit a knight's jump from the same square. Look for kings and queens on the same colour.
Solve it on the board above, or take a hint. Every ChessLvl puzzle is checked by a chess engine to have exactly one best move.