BB 100bb Defense
BB 100bb Defense
The strategy and range adjustments used by the player in the big blind position to defend (call or raise) against a preflop open raise when effective stacks are 100 big blinds deep.
Introduction
BB 100bb Defense refers to the optimal range and decision-making process for the big blind (BB) when facing a preflop raise and both players have 100 big blinds (bb) effective stacks. At 100bb, stack depth allows for standard postflop play without the immediate threat of commitment, making defense primarily about pot odds, equity realization, and positional disadvantage.
Key Principles
Pot Odds and Required Equity
The BB already has 1bb invested. When facing a 3bb open raise, the BB must call 2bb to win 4.5bb (including the small blind). This gives direct pot odds of 2:4.5, requiring approximately 30.8% equity against the opener's range. However, because the BB acts first postflop (positional disadvantage), they need more equity in practice—typically around 35-40%—to compensate for the inability to realize equity optimally.
Range Construction
A standard 100bb defense range from the BB against a typical 2.5-3bb open includes:
- Strong hands: 3-bet for value (QQ+, AK, sometimes AQs, JJ).
- Medium strength hands: Flat call (e.g., 77-TT, suited connectors like 87s, suited aces like A2s-A5s, some offsuit broadways like KQo).
- Weak hands: Fold (e.g., 32o, Q6o, etc.).
The exact range varies by opener's position. Against an early position raise, the BB defends tighter; against a button raise, the BB defends wider, sometimes calling with over 50% of hands.
The Role of 3-Betting
At 100bb, the BB can 3-bet both for value and as a bluff. Common 3-bet bluffs include suited aces (A2s-A5s), suited connectors (65s, 76s), and some offsuit connectors (KJo). The goal is to balance the range and make the opener's life difficult. 3-bet sizing is typically 3-4x the open (e.g., 9-12bb total).
Common Mistakes
- Over-defending: Calling with too many weak hands (e.g., Q2s, J4s) leads to postflop losses due to positional disadvantage.
- Under-defending: Folding too often allows the opener to profitably steal blinds. The BB must defend enough (typically 50-70% depending on opener's position) to make the opener indifferent to stealing.
- Passive play: Not 3-betting enough with strong hands or bluffs, making the defense predictable.
Postflop Considerations
After calling, the BB is out of position. The focus is on check-raising strong draws and value hands, leading with some suited hands, and checking most of the range. At 100bb, the BB can profitably call flop bets with hands that have implied odds (e.g., gutshots, low pairs) due to deep stacks.
Conclusion
BB 100bb Defense is a balancing act between pot odds, equity realization, and positional disadvantage. A solid understanding of ranges, 3-betting, and postflop play is essential for a profitable defense strategy.