按钮位翻前下注跟注彩虹面（BTN Preflop Bet-Call Rainbow）

Term Composition

• BTN: Button position. The player in the dealer position acts last preflop and second-to-last postflop unless there is a raise.
• Preflop: The stage before the flop, where players only hold two hole cards and have not seen any community cards.
• Bet-Call: A sequence of actions where a player first bets, then calls after being raised. Typically indicates the player voluntarily bet, was raised by an opponent, and then chose to call.
• Rainbow: Refers to the flop where the three community cards are all of different suits, reducing the possibility of flush draws. This influences the range assessment of the preflop bet-caller.

Typical Situation

This term is commonly used to analyze the Button player's mixed aggressive and passive strategies preflop. For example:

• The Button opens with a bet holding a medium-strength hand (e.g., AJo, KQo). When the blind player 3-bets, the Button calls. The flop comes rainbow (e.g., ♠8♦5♣2).
• A rainbow flop means there is no obvious flush draw. Therefore, in the Button's calling range, suited hands (e.g., suited connectors) are reduced, while made hands like top pair, pocket pairs, or straight draws are more likely.

Strategic Significance

In this scenario, the rainbow flop makes the preflop caller's range lean toward made hands or straight draws rather than flush draws. On subsequent streets, the preflop aggressor (typically the opponent) must account for this information to balance bet sizing and hand strength. For example, on a dry rainbow flop, the preflop raiser may use more continuation bets (c-bets) to represent strength, while the preflop caller may call or raise with medium pairs, bottom pairs, etc.

Notes

This term is not a fixed play but describes a common scenario where a specific preflop action aligns with flop texture. In practice, decisions should account for factors such as stack depth, position, and opponent tendencies.