progressBB defense vs CO open at 23 BB
8-max MTT · ante 12.5 % · Cutoff opens, small blind folds · chip EV
How the BB defends at 23 BB
Facing a Cutoff open to 2 BB (small blind folds) with 23 big blinds, the big blind folds only 16% of hands, calls 66%, 3-bets to 6.5 BB with 3.8% and goes all-in with 13%. The big blind already has one blind in the pot and closes the action, so it gets a good price.
Always 3-bet: AA, AQs, ATs.
Always all-in: AKo, AQo, AJs, AJo, ATo, A9o, A5o, A4o, K6o, QQ, JJ, 99, 88, 77, 66, 55 and 2 more.
Folded: Q5o, Q3o, Q2o, T5o, T4o, T3o, T2o, 94o, 93o, 92o, 83o, 82o and 3 more.
Against other openers at 23 BB the big blind continues with: vs BTN 88%, vs HJ 79%, vs LJ 77%, vs UTG+1 74%, vs UTG 73%. The later the opener, the wider its range, and the more the big blind defends.
Closest decisions (the book continues with them only part of the time): 84o 58%, J3o 72%, J2o 26%. These are the hands worth drilling, because a small change in the opponents or the stack flips them.
What changes around 23 BB
The book continues with 84% of hands here, 84% at 22 BB and 84% at 24 BB. Going from 22 BB to 23 BB, no hand crosses the 50% line; only the frequencies shift. With the extra chips some former all-ins become small raises: AKs, ATs, KK, KQs.
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Numbers come from the progressGTO solution book (v14, chip EV, 8-max, ante 12.5 %): our own equilibrium computation with a modelled postflop. It is an approximation, not an exact solution, and it keeps improving. Hover or tap a hand to see its exact frequencies.
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