progressBB defense vs BTN open at 21 BB
8-max MTT · ante 12.5 % · Button opens, small blind folds · chip EV
How the BB defends at 21 BB
Facing a Button open to 2 BB (small blind folds) with 21 big blinds, the big blind folds only 14% of hands, calls 63%, 3-bets to 6 BB with 2.1% and goes all-in with 22%. The big blind already has one blind in the pot and closes the action, so it gets a good price.
Always all-in: AA, AKo, AQo, AJo, ATs, ATo, A9s, A9o, A8s, A8o, A7o, A6s, A6o, A5s, A5o, A4s and 13 more.
Folded: Q4o, Q3o, Q2o, T3o, T2o, 94o, 93o, 92o, 83o, 82o, 73o, 72o and 1 more.
Against other openers at 21 BB the big blind continues with: vs CO 84%, vs HJ 80%, vs LJ 78%, vs UTG+1 75%, 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): T5o 50%, 84o 52%, Q5o 60%, T4o 26%. These are the hands worth drilling, because a small change in the opponents or the stack flips them.
What changes around 21 BB
The book continues with 86% of hands here, 85% at 20 BB and 87% at 22 BB. Compared with 20 BB, these hands come into the range: T5o, 84o. With the extra chips some former all-ins become small raises: QQ.
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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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