In short: One side of the board. The queenside is the side where the queens start, the kingside the side where the kings start.
Also called wing; queenside and kingside.
A flank, or wing, is one side of the board. The kingside is the side where the kings start, the queenside the side where the queens start. Between them lies the center.
There are two ways of counting. Strictly, the queenside is the a-, b- and c-files and the kingside the f-, g- and h-files, with the d- and e-files as the center. Often the board is simply split down the middle instead, a to d and e to h. Neither is wrong, and it is usually clear from the context which is meant.
Where is the king?
After castling kingside the king stands on the kingside, after castling queenside on the queenside. See castling. It affects the whole game. The pawns in front of the king should preferably stay put and shelter it, while the pawns on the other wing can advance without risk to your own king.
If the players have castled on opposite sides, it often turns into a race: both attack on the wing where the opponent's king stands. Read more about opposite-side castling.
Play on the wing
When the center is locked by pawns, the play often moves out to the wings. The side with more pawns on a wing can try to create a passed pawn there. The side with fewer can still attack, as in a minority attack on the queenside.
Frequently asked questions
Which files make up the queenside?
Strictly, a, b and c, with the kingside then being f, g and h. Often the board is split down the middle instead, so that the queenside is a to d and the kingside e to h.
What does it mean to play on the queenside?
To advance pawns and pieces on that side, often to open lines or create a passed pawn. If both kings have castled kingside, the queenside pawns can advance without weakening either king.
Updated November 14, 2026