Four bet
also called 4-bet
A four bet is the third raise in a betting round: someone opens, someone raises that, and the four bet raises again.
Before the flop it is a strong action by definition, because it beats a range that already showed strength twice. That is why four betting ranges are narrow and why the size is usually smaller in proportion than the raise before it.
Once stacks get shallow the four bet stops being a bet and becomes a commitment. At around 40 big blinds a four bet already puts a large part of the stack in, so the plan for what happens if the opponent moves all in has to be made before the raise.
an example
your cards
A player opens to 3 big blinds, you raise to 10, and they raise to 24. With ace king you can call or move all in, and the choice depends almost entirely on how wide their three bet was, not on how the hand looks.
This example is made up. The real one is in your own hand history: find four bet in your own hands and see how often it came up and what it cost you.
related terms
Three-bet
A three-bet is the second raise in a betting round, counted by treating the big blind as the first bet, the opening rais ...
Open raise
An open raise is the first voluntary raise of a hand, made when everyone before you has folded and nobody has yet put mo ...
Range
A range is the whole set of hands a player could hold in a given situation, rather than a guess at the one hand they act ...
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Knowing the word is not the same as seeing it.
Forty hands against a bot, no account, and your own hand history at the end.