Attacking Initiative

The initiative belongs to the player who can make threats that cannot be ignored, such as checking the opponent's king. They thus put their opponent in the position of having to use their turns responding to threats rather than making their own, hindering the development of their pieces. The player with the initiative is generally attacking and the other player is generally defending.

If you want an attacking game, castling to the opposite side of the board than your opponent is the easiest way to do this. The reason is that then the pawns in front of your opponent's king can be pushed forward to participate in an attack. If you want a safe game, for example when your opponent has a lead in development, castle on the same side as your opponent. If your opponent tries to push the pawns on the same side as the kings, you will frequently be able to counter-attack. When in doubt, kingside castling is almost never "wrong", but queenside castling is sometimes a grave error.

In the following worth-solving puzzle, White is to play and attack.