Training notebook · Tactics
X-ray attacks: read what lies behind the first piece
An x-ray attack matters when a line piece can influence something beyond an intervening piece after a change. Train the hidden alignment without pretending that a rook or bishop can currently move through an occupied square.
A position to work through
Calculate a candidate continuation without moving the pieces. Look for the tactical idea, consider the opponent’s reply, then compare your calculation with the recorded line.
White to move
Compare with the recorded continuation
Rxf8+ · Rxf8 · Rxf8#
This is a line from the training source, not a claim that every alternative has the same outcome. Calculate the opponent’s reply before revealing it.
Lichess CC0 puzzle database; position from Brass Pawn’s curated training data
Separate present attacks from future contact
Follow a rook, bishop or queen's line until it meets a piece, then inspect what lies behind that blocker. The rear target is not necessarily attacked directly now. Its relevance depends on a capture, exchange or move that opens the route.
Write the opening event in words. Perhaps the blocker can be exchanged with check, or a recapture will place a valuable piece on the line. Without that event, the x-ray is a positional clue rather than an immediate tactical win.
Calculate the exchange that activates the line
When a capture occurs on an aligned square, update every line piece affected by the removal. A rook behind another rook may become a recapturer. A bishop behind a pawn may begin defending an important square. The apparent material count can change abruptly once the blocker disappears.
Do not double-count a rear defender while its line remains blocked. Equally, do not forget it after an exchange has opened the route. The exercise is about recalculating the board state at the correct moment.
Turn line awareness into a safety check
Before placing a queen behind a piece on an opposing rook's file, inspect forcing exchanges of that piece. Before capturing a defended piece, check whether its departure uncovers a second recapturer. These short questions catch many hidden tactical dependencies.
In analysis, compare the position before and after the critical exchange. Name the newly active attacker or defender. That explanation is more useful than writing 'x-ray' next to a move and leaving the reason implicit, especially when several line pieces share the same file or diagonal.
Find hidden recapturers behind the front piece
A rear piece can matter defensively as well as offensively. Before announcing that a rook is undefended, inspect whether exchanging the front defender reveals another rook behind it. Before deciding a capture is safe, look for a queen newly connected to your king. These checks do not require predicting a long combination. They require updating line geometry after a small change. Short accurate exchange exercises are therefore useful even when they seem easier than the elaborate tactics you usually prefer to solve during a training session.
Update blocked lines after each exchange
Choose five positions with at least two line pieces facing along a file or diagonal. Before solving, list which lines are blocked and what specific exchange could open each one.
After every move in your chosen line, update the list. Stop if you have mentally allowed a piece to move through an occupied square. Use the board to reconstruct that branch, then calculate again without moving pieces. This targets a visualization error that quick motif recognition alone does not fix.
Put the practice into a routine
Where Brass Pawn fits
Brass Pawn's local engine analysis and tactics positions can help test x-ray calculations. Follow actual legal moves on the board; an engine evaluation is not a substitute for identifying the precise exchange that brings a hidden attacker or defender into play.