CO位河牌平跟（同花面）（CO River Flat Call Monotone）
The action of the CO player only calling rather than raising on the river when the flop is monotone.
Explanation of the Term
CO River Flat Call Monotone refers to a player in the cutoff position (CO) who, on a monotone board (i.e., all flop cards of the same suit) and after the river card is dealt, chooses only to flat call facing an opponent's bet, without raising or folding.
Strategic Background
A monotone board usually implies the possibility of a flush draw or a made flush. As a late position, the CO has a wide preflop raising range and may have many draws or made hands postflop. When facing a bet on the river, a CO player's decision to flat call is typically based on the following considerations:
- To avoid being bluffed or value-raised by a better flush;
- Showdown value is sufficient to win the pot, but not enough to raise for value;
- To balance the range, preventing opponents from easily folding when they read a strong hand.
Typical Scenario Example
Assume the flop is A♠ K♠ 9♠ (monotone spades). The CO might historically hold a big flush draw like Q♠ J♠, or a weaker flush draw and top pair. If the river is a blank like 2♦, and the opponent bets about two-thirds of the pot, the CO, holding top pair with a flush draw (which did not complete), might choose to flat call because raising would only get called by better hands, and the opponent might be bluffing on this board.
Notes
This term itself does not imply whether the decision is correct or not; it merely describes a betting action. In practice, it should be evaluated in conjunction with pot odds, opponent tendencies, range balance, and other factors.