枪口河牌第五次加注彩虹面（UTG River 5-Bet Rainbow）

Term Formation

• UTG (Under the Gun): The first position to act preflop, located to the left of the big blind.
• River: The fifth community card in Texas Hold'em, i.e., the river card.
• 5-Bet: The fifth raise, meaning a re-raise after a 4-bet. It occurs more often preflop and is extremely rare postflop.
• Rainbow: Refers to a board where all community cards are of different suits (e.g., all five cards – flop, turn, and river – are different suits). In such a scenario, no flush draw is possible.

Usage and Strategy

This term is not a standard poker term but is mostly seen in advanced strategy discussions or teaching examples. It describes an extreme scenario: an UTG player re-raises (5-bets) after facing a 4-bet on the river, and the board is a rainbow.

• Hand Strength Interpretation: A 5-bet on the river almost only occurs in no-limit Texas Hold'em and typically indicates that the player holds the nuts or a very close equivalent, such as the top of a straight flush. A rainbow board eliminates the possibility of a flush, so hand strength relies more on made hands (e.g., straights, sets, two pair, etc.).
• Positional Factor: The UTG position is the most disadvantageous preflop, but on the river, positional advantage is less pronounced. However, an UTG player voluntarily raising to a 5-bet shows extreme confidence in their hand.
• Opponent's Range: An opponent who can call or raise to a 4-bet also likely has a strong hand, so the UTG's 5-bet often forces the opponent into a difficult decision.

Common Misconceptions

• This is not a common term in formal tournaments or cash games; it is mostly used in theoretical analysis.
• In actual play, a 5-bet on the river is extremely rare because bet size limits are usually constrained by stack depth and table dynamics.

Related Terms

• UTG (Under the Gun)
• 5-Bet (Fifth Raise)
• River (River Card)
• Rainbow (Rainbow Board)
• 4-Bet (Fourth Raise)
• Nuts (Best Possible Hand)