MP 20bb Defense

Overview

MP 20bb Defense is a concept in no-limit hold'em tournament strategy that describes the correct approach for a big blind (BB) player facing a raise from middle position (MP) when the effective stack size is around 20 big blinds (bb). This is a critical stack depth where decisions often revolve around preflop all-in or fold, but with 20bb, there is room for post-flop play if the stacks are managed carefully.

Key Considerations

Stack Depth Dynamics

At 20bb, the stack-to-pot ratio (SPR) after a standard raise (e.g., 2.2-2.5bb) is low, meaning that post-flop play is often all-in or committed. However, compared to shorter stacks (10bb or less), there is some flexibility to call and see a flop, especially when the big blind has a defending range that can navigate post-flop decisions.

Position and Range

Middle position raises typically represent a tighter range than late position but wider than early position. A standard MP opening range at 20bb might include premium hands (TT+, AQ+) and some suited connectors or broadways. The big blind's defense range should account for pot odds, the raiser's range, and the fact that the BB will be out of position post-flop.

Defending Strategy

• Calling Range: Hands that can flop well or have good equity against MP's range, such as suited aces, suited connectors (e.g., 65s), medium pairs (55-99), and some offsuit broadways. Avoid calling with hands that are easily dominated (e.g., ATo, KJo) unless the opponent is particularly loose.
• 3-Bet Shoving: With 20bb, 3-bet shoving is a common move. Hands like TT+, AJ+ are typically strong enough to shove for value, but also some bluffs with blockers (e.g., A2s, K9s) can be used to balance. However, avoid over-bluffing as MP will have a strong calling range.
• Fold: Weak hands with poor playability, such as low offsuit cards, should be folded.

ICM Implications

In tournaments with ICM pressure (especially near the money or at final tables), the defense range should tighten. Defending too wide can lead to marginal spots that jeopardize tournament life. Conversely, if the raiser is under ICM pressure, the BB can attack with a wider range.

Example Defending Range

A typical 20bb BB defense vs MP open might include:

• Call: 55-99, A2s-A9s, K9s+, Q9s+, J9s+, T9s, 98s, 87s, 76s, sometimes ATo/KJo/QJo if opponent folds too much post-flop.
• 3-bet shove: TT+, AJ+, ATs, sometimes KQo, A2s-A5s as bluffs.
• Fold: everything else, especially low offsuit cards and weak suited gappers.

Common Mistakes

• Defending Too Wide: Calling with weak hands that cannot profitably play out of position at low SPR.
• Ignoring ICM: Using the same strategy in all tournament stages.
• Inconsistent Sizing: Not adjusting to opponent's raise size (e.g., facing a min-raise vs. a larger raise).

Conclusion

MP 20bb Defense requires a balanced approach between pot odds, equity realization, and tournament factors. It is a nuanced spot where experience and opponent tendencies matter greatly.