The principle of narrowing the range is the basis of the poker strategy

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Poker is an intellectual game with incomplete information. The main part of the hidden information is the opponent's pocket cards.

To win in this game, you need two basic skills:

1. Learn how to "read" the opponent's cards as best as possible;
2. Learn how to give out as little information about your cards as possible. 

You can imagine this in the form of attacking characteristics (reading the opponent's hands) and defensive characteristics (hiding and blurring the understanding of our hand in the eyes of the opponent).

1. The fundamental principle of a poker player's mindset

This article describes the main attacking principle of our strategy – the principle of narrowing the range: What is the range of hands in poker?

This principle is based on the initial ability to set the range to the opponent from preflop and the subsequent exclusion from the spectrum of the opponent of a part of the hands on each street by analyzing each of his actions (decisions). The opponent's range narrows after each decision made, like a jet of water as it passes through the funnel. To successfully read hands on each street, it is necessary to keep in mind the range of the previous street. 

At the beginning of the hand, we only have the basis – this is the preflop range of the opponent, which we deduce from two main characteristics:

1. The average range of the game at the field of players in this preflop action;
2. The displayed statistics (HUD) for a particular player or our observations of his game. 

The bottom line is that the villain with his preflop range on the flop gets several options for the number of buttons in the room: fold, check, bet. Or if we bet against it, then fold, call or raise. Thus, the opponent's choice of any of the action options will mean only a part of his preflop of the range on which he wants to play this particular action. This is often called tree branches, where the choice of any of the actions begins its game branch. It is at this point that our reading of the opponent's hands is included, we analyze which hands will fall into which branch of his preflop range.

As can be seen from the picture above, the number of possible combinations of opponent's cards decreases after each decision made. Here, it is also important to understand that those combinations that went to another branch (for example, to the check branch when the opponent made a bet) do not appear further on the following streets. They are excluded. Thus, the process of reading hands on each street is based on the range of the previous street. If you assumed that on the turn the opponent's range consisted of a draw hand and top pairs, but did not include sets, then on the river the sets cannot suddenly reappear in its spectrum. A similar mistake in thinking is made by many novice and inexperienced players who set the range on each street in isolation from the spectra of the previous ones, which is a conceptual mistake.

At a fundamental level, our entire post-flop strategy is based on just two factors:

1. Range of the opponent, converted into variants of his hits in the board
2. Understanding his playing strategy against us with every part of this range

How to set and narrow an opponent's range 

1. First of all, learn to set the correct preflop range for the opponent, because further narrowing of the range is based on it.
2. Put yourself in your opponent's shoes and evaluate his action as if you were doing it. What will you put on this board? What will you be waiting for? Which hands are you ready to play on the stack?
3. The way you see your own drawing branches with different types of hands in this board is the basis of the laid range.
4. Next, you learn to edit the range based on the experience of playing with your opponents and analyzing their statistics. Some opponents will play in a similar way to you, while others will have serious differences in the ranges of the game.

In order to qualitatively set range for other types of players, you also need to know: 5 types of poker players, and how to play against them. 

Corrections when working on the principle of narrowing the range

Using the principle of narrowing the range, on each street you exclude from the range of the opponent certain hands that can no longer appear in his spectrum on later streets. However, in some situations, it may happen that the hands that you have already excluded become likely again due to the actions of the opponent.

This happens for three reasons:

1. You are just learning to work on the principle of narrowing the range and narrowing errors are inevitable, but over time they will become less.
2. Sometimes opponents choose illogical lines, excessively play slow play or vice versa add illogical bluff to the line.
3. Sometimes opponents try to play very cunningly.

In view of this, some logical improvements to the range are possible on later streets, but this should be the exception, but not the rule. The process of reading hands begins with the average range of the opponent on the preflop. Further, this range can be narrowed street by street by excluding certain hands with which the opponent would choose another line of the draw. Hands that were excluded from the range of an opponent on one of the streets can no longer (with rare exceptions) reappear in his spectrum. Following this principle, you will narrow your opponent's range as the draw progresses. The better you evaluate an opponent's range, the better your decisions against him.