Fundamental Poker Theory Explained

The Fundamental Theorem of Poker is the bedrock of the modern poker game and my guide explains it all, including examples of how it works.

Last Updated on February 15, 2024 by Avatar Author Adrian Sterne
Fact checked by Dusan Jovanovic
Image of Fundamental Poker Theory in PokerThe fundamental theorem of poker is a groundbreaking concept first introduced by the professional poker player and three-time WSOP bracelet winner David Sklansky in his book Theory of Poker in 1979.

What’s great about this theorem is that it’s universal — it applies to every variation and format of poker. It captures the essence of poker and its nature as a strategy game about making decisions without having all the information.

Every winning poker player follows this seemingly simple yet profound axiom to the letter.

This post will explain fundamental poker theory and help you improve your poker skills.

What Is the Fundamental Theory in Poker?

What Is the Fundamental Theory in Poker?

The fundamental poker theory asserts that you must make decisions at a poker table as if you could see your opponent’s cards. It emphasizes the importance of getting a read on your opponent and understanding their ranges.

I will quote the first part of the theory directly from the book and then provide an interpretation:

“Every time you play a hand differently from the way you would have played it if you could see all your opponents’ cards, they gain; and every time you play your hand the same way you would have played it if you could see all their cards, they lose.”

Based on the belief that you can see your opponents’ cards, this part implies that you should always make mathematically sound decisions:

  1. Bet or raise if you have a strong hand.
  2. Fold if you have a weak hand.
  3. Bluff-raise if your marginal hand is slightly better than your opponent’s.

While you can’t see your opponent’s hands, you can make an educated guess by reading body language and narrowing down their ranges.

The second part of the theorem mirrors the first part but from a different perspective:

“Every time opponents play their hands differently from the way they would have if they could see all your cards, you gain; and every time they play their hands the same way they would have played if they could see all your cards, you lose.”

This part highlights the importance of bluffing and preventing opponents from getting a read on you. It suggests mixing things up, using different patterns at the table, and using versatile ranges across the board.

Example of the Fundamental Theory

Let’s pretend we’re playing a $1/$2 No Limit game with $200 stacks.

  • Player A is dealt J♣ J♦
  • Player B is dealt 9♠ 8
  • The board: A♣ 2♠ J

Image of Fundamental Poker Theory Example

Let’s say player B bets $20 into a pot of $20. According to fundamental poker theory, player A should call in this scenario. Even though player A has the better hand and knows at this point that their opponent is bluffing, they should avoid raising because it would scare player B away.

Rather than raising, player A should wait until his opponent puts more money into the pot. In this situation, calling has a higher expected value, which is what fundamental theory is all about — focusing on making players with the largest EV.

Is Fundamental Theory Effective?

The fundamental theory is the cornerstone of every successful poker strategy. Even though it’s described in everyday language, it’s based on math.

Applying this concept requires in-depth knowledge and skills because of the numerous variables in every poker game.

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Poker’s fundamental theory is based on the premise that the only correct play is one that has the highest expected value. Deviating from this pattern will negatively affect your long-term win rate.

The better you read your opponents and widen your range, the more successful you’ll be.


Does the fundamental theorem of poker apply to every situation?

The fundamental poker theory is universal and can be applied to any variation or format of poker. In contrast, most other poker theories apply only to specific situations and variations.

What is discussed in the fundamental theorem of poker?

It talks about how players should always make decisions with the highest EV. This is done by assessing the opponent’s range and obscuring your own patterns.

Does the fundamental poker theory work?

Fundamental poker theory is axiomatic, but it takes an adept player to apply it effectively.

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