# Gap principal math

• Bronze
Joined: 27.11.2010
My question pertains more to tournaments. I was wondering if someone could help me out (I'm not exactly naturally mathematically minded). My question is; how can I calculate a profitable calling range against opponents that I have history with based on the gap principal?For example if someone is shoving top 30% of hands from the cutoff with 11bb what % of hands can I call with? I've read in some places it's top 40% of the opponent's range so I could call with top 12% of hands here if they are shoving top 30%. This seems too general though and I haven't actually seen any math to back this up. Could someone please explain it a little or post an example? Thank you!
• 3 replies
Joined: 23.03.2011
Hey sooley,

The GAP concept is opponent specific, Depending on the opponents tendencies, the gap should be wider for tight opponents and narrower for looser opponents.

For instance:

Example #1: You have Ace-Jack suited on the button. An extremely tight player who you have only seen raise three times, and every time it was a big pair or big ace, has raised to 4x the big blind from early position. Many players would call here because of their positional advantage. If you are applying the Gap Concept you should fold because of the likely strength of your opponent's hand. I'm not saying you should always fold Ace-Jack suited in this situation, but it's something you need to consider. What are you going to do if the flop comes jack high? Ace high? By calling with trouble hands such as these in situations where your opponent's likely hands have yours dominated, you will find yourself facing very difficult decisions post-flop and can end up costing you a significant amount of chips. The Gap Concept is trying to help you avoid these difficult confrontations by saying “fold here please.”

Example #2: Same hand and position as in Example #1, only this time the player who has raised from early position is a maniac who has raised 8 of the last 12 hands. Now your gap is small and the strength of a hand like Ace-Jack suited is high. Applying the Gap Concept here, not only could you call... but you should more than likely raise because the probability that your hand is the best hand here is high.

Sourced from betandskill.com

Regards

Laz
• Bronze
Joined: 15.06.2009
To make the situation "clean", assume you are in the BB and it is folded around to you.

First thing to do is to calculate pot odds. It is at least 12.5:10, and I suppose there's antes too. So, you'll have maybe 1.4:1 to call. You can call much much much wider than you suggested. With 1.4:1 in odds, you can profitably call with hands as bad as close to the bottom of your opponents range. Say he shoves all Ax. Then call with A4, but fold A2.

I suggest you read Harrington's tournament series. This is explained very well in volume two.
• Silver
Joined: 11.10.2015
Big thaks to you.