小盲河牌冷跟彩虹面（SB River Cold Call Rainbow）

Term Composition

• SB: Small Blind, the position that must post the small blind preflop, typically the first player to the left of the dealer.
• River: The betting round after the fifth community card is dealt.
• Cold Call: To call a raise without having previously put any dead money (e.g., blinds or antes) into the pot. Usually occurs preflop or on the flop; less common on the river but theoretically possible.
• Rainbow: A board where all four (or three) community cards are of different suits, eliminating the possibility of a flush draw. On the river, a rainbow board means all five community cards are of different suits.

Meaning of the Term

This term describes a specific scenario: from the Small Blind position, on the river, with a board showing four or five different suits (i.e., rainbow), and the SB player has not previously participated in the betting of that hand (i.e., has not put in any dead money). Facing a bet from an opponent, the SB chooses to call. Such a call typically indicates the player holds a strong hand, such as a set or a straight, since the rainbow board rules out any flush possibility, and the cold call suggests the player may have been hiding their hand strength.

Strategy Points

• Cold calling on the river generally requires caution, as an opponent’s bet often represents a strong range.
• A rainbow board reduces the chance of flushes, so players should focus more on the strength of made hands like top pair, two pair, or straights.
• Cold calling from the Small Blind may reveal information about hand strength, as the SB is usually at a positional disadvantage postflop.

Usage Example

The hand reaches the river with a board of A♠ K♥ Q♣ J♦. The pot is large. The SB player has been folding throughout and now faces a river bet from the turn raiser. He cold calls. Since the board is rainbow, he likely holds 10-9 for a straight.