Roadmap > Tactics > Targets > Undefended Pieces
Example of Targeting an Undefended Piece
White to move. 1. Qc8+ Kg7 2. Qb7+ forks the exposed black king and undefended bishop.
In the initial position, the black bishop on b2 was undefended. Even though it was not under attack in the initial position, it later became a target in the tactical combination.