CO Flop Open Rainbow
CO Flop Open Rainbow
A flop texture where all three cards are of different suits and unpaired, with no immediate straight or flush draws, occurring when the player in the cutoff position has opened preflop.
Definition
CO Flop Open Rainbow refers to a specific flop texture that arises when the player in the cutoff (CO) position raises preflop, and the flop comes with three cards of different suits (rainbow) and no pair, no connected cards that form a straight draw, and no flush draw. This results in a dry, low-variance board where strong hands are polarised and drawing hands are rare.
Strategic Implications
For the Preflop Raiser (CO)
On an open rainbow flop, the CO typically holds a range advantage because their preflop raising range contains many high card combinations and some suited connectors. However, since the board offers no draws, the CO should generally bet with a small size (e.g., 1/3 pot) to exploit their overall equity advantage and deny free cards to hands that might improve on later streets. The betting range should include value hands (top pair or better) and some bluffs with backdoor potential (e.g., A♠K♣ on a 9♦7♥2♠ board).
For the Defender (e.g., Big Blind)
The defender’s range is weaker overall but contains many hands that are pure air or weak pairs. Without draws to chase, the defender should be cautious: check-raising is rare except with strong hands (like sets or top-two pair). Calling a small bet with marginal holdings (e.g., second pair or a gutshot with low implied odds) may be acceptable if the opponent is likely to check back the turn.
Example Scenario
- Preflop: CO raises to 3 big blinds, Big Blind calls.
- Flop: K♠9♦2♣ (rainbow, no draws).
- Action: The CO should continuation bet frequently (around 70-80% of the time) with a small size, as they hold many strong Kings and some bluffs like A♥Q♠. The Big Blind should fold most weak pairs (e.g., 8♠7♠) and only continue with top pair or better, or hands that can improve to a strong hand by the river.
Related Terms
- Rainbow Flop: A flop where all three cards are of different suits.
- Dry Flop: A flop with no obvious draws (straight or flush), similar to a rainbow flop but also often includes paired boards.
- Cutoff (CO): The position immediately to the right of the button; the second-last to act preflop.
- Continuation Bet (C-bet): A bet made by the preflop raiser on the flop.