关位翻牌圈第四次加注彩虹牌面（CO Flop 4-Bet Rainbow）

Term Composition

• CO (Cutoff): The position to the right of the button on a 9-handed table, with positional advantage due to being closest to the button and acting later.
• Flop 4-Bet: The fourth raise in the flop betting round. Traditionally, "4-bet" is used pre-flop to denote the fourth betting action (e.g., someone opens, someone 3-bets, someone 4-bets). On the flop, since there are fewer betting rounds, a 4-bet is rare and typically occurs in aggressive multi-way confrontations.
• Rainbow: Refers to the flop containing three cards of different suits, meaning no flush draw is possible.

Scenario Interpretation

This term usually appears in advanced strategy discussions or live commentary, describing an extreme hand state: the cutoff player makes a fourth raise on the flop, creating a large pot, while the board is rainbow, meaning opponents' drawing ranges are narrower and value comes mainly from made hands or pairs. The CO's action typically represents very strong hand strength (e.g., top set, top two pair) or a pure bluff, because a flop 4-bet requires significant chips and the rainbow board reduces the rationale for bluffing.

Notes

• This term is not a standard rule term but a composite expression from online poker communities (e.g., forums, advanced videos).
• In practice, a flop 4-bet rarely occurs because the flop betting round defaults to fewer raises — typically one bet, one raise, and one re-raise are enough.
• "Rainbow" only describes the board structure and does not affect the betting action itself, but it is often mentioned together to emphasize the lack of draws on the board.