Ponderchess / Special moves
Move two pieces together. Give your king a safer home.
The king moves two squares toward the rook.
The rook lands on the square the king crossed.
The king cannot start, cross, or finish in check.
Play the guided film, or select a scene to pause and study its position.
Rule
Castling in 3D
Castling is the only move in chess where two pieces move at once: the king and one of its rooks.
Rebuild the sequence yourself. The board responds to each move, and hints are available.
Two pieces · One move
White’s back rank, shown from White’s side. Black uses the same pattern on rank 8.
A movement diagram, not a full position. Before castling in a game, check all three rules below.
The king and the chosen rook must both retain their castling rights.
Clear every square between them, including b1 when castling queenside.
It cannot start in check, cross an attacked square, or land on one.
Click or drag to move · Arrow keys + Enter to play
Your turn · white to play
Select a piece, then its destination. Switch to 2D for a clear overhead view or rotate the 3D board to explore the position.
Watch the king and rook move together, on both wings, and see why an attacked square makes castling illegal.
Idea 01
Idea 02
Idea 03
Watch the king and rook move together, on both wings, and see why an attacked square makes castling illegal.
Keyboard: Space pauses, the arrow keys step. Gold arrows are White's moves, violet are Black's, red rays are threats, green shows support, blue shows plans.
Make the idea yours
No timer. No score. Just a moment to check your understanding.
