The concept of GAP is pretty straightforward, and was first put forward by the great David Sklansky. He says something like:
“You need a stronger hand to call a raise than you do to make a raise.”
The concept sounds simple, and it is. But like many simple ideas, it can be too obvious and can become complicated. Many good players already understand this concept, especially those who play a tight-aggressive style. Inexperienced players, on the other hand, end up ignoring the gap, which leads to leaks in their playstyle.
By using the GAP correctly, you avoid three problematic situations in your game:
1: Losing the “initiative”: When you are the initial aggressor, you can win the hand in two ways: by making a really strong hand, or by betting and knocking your opponent out of the hand before showdown. When a pot has already been raised, some hands that would be playable with a raise become useless if played passively (by calling the raise).
2: Domination: Many micro and low stakes players understand the basics of position, and with that, they will raise with stronger hands from early position, and weaker hands from late position. To show what the GAP concept has to do with this, let's use an example:
You have :Ah :Js in MP2, in a full ring game and no one has entered the hand yet, so this would normally be a hand to raise. But if UTG opens a 4xBB raise and he is a tight player, then you have to think carefully. What hands would he open with from this position? Typically something between 77-AA, AQ and AK. Now think about the equity AJ has against these hands. You are either in a coinflip, or totally dominated.
3: Getting “squeezed”: The “sandwich effect” (also cited by David Sklansky) occurs when someone raises before you, you call, and someone re-raises after you, leaving you in a completely uncomfortable situation (a play also called a squeeze). Folding is tricky, since you’ve already invested money in the pot. Calling is tricky, since both opponents represent strong hands and you’re the only one with passivity in this situation.
Applying GAP Concept pre-flop
Now that you know the three problems that arise when you ignore the gap, you will be able to better apply the concept in preflop situations. The application is quite simple: you reduce your range when you are facing aggression, and increase it when you are the initial aggressor.
How strong your hand needs to be depends on things like opponent reads, table tendencies, etc. Against a loose/aggressive player or a maniac, the concept loses some value, as these players play with a lot of bad hands and their raising does not necessarily indicate strength. Against a tight or unknown player, your hand should be at least stronger than the bottom (the weakest hands) of the initial aggressor's range if you want to engage against him.
Understanding this concept will get you out of sticky situations, and will also help you better apply the real power of the concept of table positions. Practice it!
Article translated and adapted from: Gap Concept
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