Castling

Castling is the only time in chess that two pieces can move at once, and the only time any piece other than the knight can move over another piece

You can castle to either rook. Select the king to show the available moves

Selecting the rook will cause the king to move two spaces to the right or left, and the rook will move to the other side of the king

The same will happen if you castle to the left

There must be no pieces between the king and the rook

And your king and rook must not have moved yet in the game

And your king cannot be in check