To clarify, a pre-flop 4-bet refers to when a player raises after another player has raised (3-betted) the raise-first-in. Since post-flop 4-betting does not happen often and this action most commonly occurs in pre-flop situations, this article will look solely at the pre-flop side of things. A 4-bet is when a player makes the fourth bet/raise on any street.
Having a well-constructed 4-betting range will make you a nightmare to play against at the poker table.
