小盲河牌五加注彩虹面（SB River 5-Bet Rainbow）

Term Background

The SB River 5-Bet Rainbow occurs on the river in Limit Hold'em. The small blind (SB) is out of position but exploits the opponent through an extremely aggressive number of raises (the fifth raise). A rainbow board means there is no possible flush on the community cards, reducing the opponent's drawing range and making the SB's value raise safer.

Typical Scenario

• Board: e.g., A♠ K♦ 10♣ 5♥ 2♠ (the last card 2♠ makes the board non-pure rainbow? Note the strict definition: the first four cards on the river must be of different suits; the last card is irrelevant; usually the flop or turn already constitutes a rainbow).
• Action: The SB holds the nuts or a very strong hand, such as A-A or top set, and keeps raising on the river up to the fifth bet, forcing the opponent to pay off with marginal hands.
• Limitation: In limit games, the number of raises is usually capped (e.g., a maximum of four), but some rules allow unlimited raises; in such cases, a fifth raise is an extreme aggression.

Strategic Significance

This play relies on precise hand reading and board structure. A rainbow board reduces the opponent's flush draws, lowering the risk of being re-raised. By raising frequently, the SB maximizes value while denying a free showdown. However, one must consider the opponent's range and avoid over-raising when the opponent might hold the nuts.

Notes

• This is not a standard term; it appears in advanced strategy discussions or specific poker theory books.
• It rarely occurs in actual games, as a fifth raise requires sufficient stack depth and opponent cooperation.