Glossary

A

Active King — A king that participates in attack or defense, not hiding passively.

B

Bad Bishop — A bishop blocked by its own pawns on the same color squares.

Building a Bridge — The Lucena technique of using the rook to block checks.

C

Corresponding Squares — Squares where kings must be positioned relative to each other.

Cut Off — Using a rook to restrict the enemy king by file or rank.

D

Distant Opposition — Opposition with 3, 5, or 7 squares between kings.

F

Fortress — A defensive position that cannot be broken despite material disadvantage.

K

Key Squares — Squares that guarantee pawn promotion if the attacking king reaches them.

L

Lucena Position — The winning R+P vs R position with pawn on 7th rank.

O

Opposition — When kings face each other with one square between; the player not to move has the advantage.

Outside Passed Pawn — A passed pawn far from the main action, acting as a decoy.

P

Passed Pawn — A pawn with no enemy pawns blocking or able to capture it.

Philidor Position — The drawing R+P vs R defense with third rank technique.

R

Rule of the Square — Visual method to determine if a king can catch a passed pawn.

S

Stalemate — Position where a player has no legal moves but is not in check (draw).

T

Tablebase — Database of perfect endgame play for positions with few pieces.

Triangulation — Moving the king in a triangle to transfer the move to the opponent.

W

Wrong-Colored Bishop — A bishop that cannot control the promotion square of a rook pawn.

Z

Zugzwang — A position where any move worsens the position; the compulsion to move loses.