Open-Ended Straight Draw
两头顺听牌
Context: Poker term: Open-Ended Straight Draw An open-ended straight draw is a type of drawing hand where your hand, combined with the community cards, can complete a straight with one of two possible cards at either end. In practice, this draw typically has 8 outs (e.g., holding 89 on a flop of 6710 means 5 and J both complete the straight). It is a high-value draw because the probability of completing it is about 31.5%, and it is difficult for opponents to accurately narrow your range. Typical scenario: You hold QJ on a flop of 1098. Any K or 7 gives you a straight, giving you 8 outs. Facing a bet, you can consider calling or raising, as completing the draw often leads to winning a large pot. However, be cautious that your opponent may already have a flush draw or a bigger straight.
Open-Ended Straight Draw (OESD)
Overview
An open-ended straight draw (OESD) is a common type of draw in Texas Hold'em. It occurs when a player's hand, combined with the community cards, forms four consecutive cards of a straight, missing one card at each end to complete the straight. For example, if a player holds 8♠ 9♠ and the board is 7♦ 6♣ 2♥, the player has 6-7-8-9 and needs a 5 or a 10 on the river to make the straight.
Probability and Odds
On the flop, an open-ended straight draw has 8 outs (4 at each end). The probability of completing the straight by the river is about 31.5% (approximately 2.2:1 odds). If considering only the next card, the probability on the turn is about 17% (approximately 4.9:1).
Strategic Points
- Value Calculation: Since there are many outs, an open-ended straight draw usually offers high implied odds, making it suitable for calling when [in position] or when [pot odds] are favorable.
- Semi-Bluff: On the flop, consider semi-bluff raising with an open-ended straight draw, because even if called, there is about a 1/3 chance of completing the straight by the river.
- Reverse Implied Odds: Be aware that opponents may hold larger straight draws or flush draws, which could result in losing even after making the straight.
Difference from a Gutshot Draw
A gutshot draw has only 4 outs, with a probability of about 16.5% from flop to river, whereas an open-ended straight draw has 8 outs, doubling the probability. Therefore, an open-ended straight draw is more worth chasing in practice.
Example
The flop is J♠ 10♣ 4♦, and a player holds Q♥ K♠. The player has Q-K-J-10 and needs a 9 or an A to complete the straight, which is an open-ended straight draw.