BTN 100bb Defense

Overview

BTN 100bb Defense refers to the decision-making process for the big blind (BB) when facing a raise from the button (BTN) in a cash game where both players have effective stacks of 100 big blinds. This is a common scenario in No-Limit Hold'em, and the BB must choose a defending range to avoid being exploited by the BTN's wide opening range.

Key Concepts

Position and Range

• The BTN opens with a wide range (typically around 40-50% of hands) because of positional advantage.
• The BB is out of position post-flop, so he must defend with a range that is strong enough to profit but wide enough to prevent the BTN from auto-profiting with any two cards.
• A typical GTO (Game Theory Optimal) defend range for the BB against a BTN open of 2.5x is around 40-50% of hands, including calls and 3-bets.

3-betting vs Calling

• The BB can 3-bet a linear or polarized range. A linear range includes strong hands (e.g., AJ+, KQ, TT+) that want to build a pot in position post-flop? Actually, BB is out of position, so 3-betting is often for value or as a bluff.
• A polarized range uses strong value hands (QQ+, AK) and weaker hands (e.g., A2s-A5s, suited connectors) as bluffs.
• Calling is typically done with hands that have good playability post-flop but are not strong enough to 3-bet for value, such as suited connectors, small pairs, and some offsuit broadways.

Adjustments

• If the BTN opens larger (e.g., 3x), the BB should defend tighter.
• If the BTN folds too often to 3-bets, the BB can increase 3-bet frequency.
• If the BTN calls 3-bets too much, the BB should 3-bet a wider value range.

Typical Defense Strategy

A balanced BB defend strategy against a 2.5x BTN open might look like:

• 3-bet for value: JJ+, AK, AQ (sometimes).
• 3-bet as bluff: A2s-A5s, K9s, Q9s, J9s, T8s, 97s, 87s, 76s (some combinations).
• Call: All pairs 22-TT (sometimes 3-bet JJ+), suited aces weaker than A2s, suited connectors 65s+, offsuit broadways (KQo, AJo, etc.), suited one-gappers like J9s, T8s, etc.
• Fold: Weak offsuit hands (e.g., Q5o, J7o) and unsuited low cards.

Example

Suppose the BTN opens to 2.5bb with 100bb effective. The BB holds 88. A typical GTO strategy might call ~70% of the time and 3-bet ~30%. With 99+ and ATs+, the BB might 3-bet more often.

Conclusion

BTN 100bb Defense is a critical skill in No-Limit Hold'em. By understanding ranges, frequencies, and adjustments, players can defend their blind profitably while minimizing exploitation. Practice with solvers and experience will refine these strategies.