Bayes' rule
Reweighting each hand in a range by how often it would take the action you just saw.
Last updated
- What it means
- Bayes' rule updates the chance of each hypothesis after new evidence. In poker the hypotheses are the hands in a range and the evidence is the opponent's action.
- How it is calculated
- P(hand | action) = P(action | hand) × P(hand) ÷ the same product summed over every hand in the range.
- Worked example
- A river range of 30 value combos and 10 bluffs bets every value hand and half the bluffs. After the bet, bluffs are 5 ÷ 35 = 14.3% of it, down from 25%.
- Why it matters
- Every bet narrows a range toward the hands that make it. Doing this sum, even roughly, is what hand reading is.
Try it: Poker math
Formula and worked example: Updating a range in poker math
Lessons that teach it: Let the bet reshape the range · lessons other than the free one need an invite
See also: Hand reading, Range, Bluff-catcher