This is indeed a tricky one…BU will be in position and so has incentive to flat a lot of hands vs your chilly4…On the other hand your are raising quite big, so BU might be willing to call less…i guess folding this is indeed an option after the 4bet

Feels like a fold to me. BTN 3b sizing vs MP is weird. I think you could potentially size down slightly with your 4b (19 to 20bb).

As a heuristic, when they 4b/5b non all in, it is generally quite nutted.

yep he got AA most of the times

Taking a look at Equilab, GTO Wiz, and taking into account how to exploit the pool at micros, I think it makes the most sense to approach this spot from the perspective of what can we do to maximize our fold equity from this spot onwards, and maximize fold equity?

I've heard before that a good decision making process is to try and eliminate one of the options and go from there. I think we wouldn't fold. Imagine we fold and he has AK. I think AK plays the exact same way BU plays here, as does AA, KK. Taking into account card removal here are the combos he has of these:

AA: 3 combos
KK: 3 combos
AK: 9 combos

Then we are flipping against QQ, 6 combos.

Power-Eq shows we have almost 40% equity VS. JJ+,AKs,AKo, and 37% equity if we exclude JJ & QQ. We have direct pot odds (28%).

GTOWiz is shown below, and I think it's useful because it has BU 4-betting a range that I think people in the Micros would 4-bet as well.

Last thing to keep in mind about the calling option, is that since the SPR is so large, that neutralizes a lot of the disadvantage of being out of position. It's really 3-bet pots that hurt to play OOP.

In the pool I play in, I would shove. It gives the opponent the chance to make a big mistake and fold AK or JJ. Furthermore, there is the chance he was bluffing some weak Axs, and now he 4-bets because he simply decides to keep bluffing.

The thought process of some bad players, is they don't think ahead, they just make one action, get pulled through the hand, and don't think about their range or their opponent's range. If even some of the time he 3-bets some hands as a bluff, that he then decides to incorrectly keep bluffing with as a 5-bet, then I think folding especially could be very bad.

Also thinking about bad players and their weird 3 bet sizings, I've been pretty much ignoring their weird sizings and I still have been 4-bet bluffing regardless, and it feels like small 3-bets aren't necessarily nutted, rather a significant portion of recs simply don't know correct 3-bet sizings.

In conclusion, I'd 5-bet shove preflop. I think calling then betting or bluffing postflop also has merit, although that'd be dependent on a lot of factors (boards, if opponent c-bets or checks, etc.).

Also, just wanted to add a note here to let me know your thoughts on this analysis, and I'm not asserting that this right / the definitive correct answer.

Polyneikos Thanks! Yeah, it sounds like a cooler to me, you're at the very top of his range, and your close to the top of yours.