Plain-English Definition
X-rays reveal pressure that is not immediate yet. Rooks, bishops, and queens can attack through a front piece toward something behind it.
Why It Matters
X-rays make line pressure visible before it becomes a tactic.
Common Signs in Games
- Valuable pieces share a rank, file, or diagonal.
- A front piece can move with tempo.
- A line can open after a capture.
Common Mistakes
- Seeing only the front piece.
- Missing x-rays against your own king.
- Opening a file for the opponent.