1-2, AKo facing 4b from euro

Probably fold unless we have crazy aggro image.

Jam or fold. Flip a coin.

‘Euro reg’ isn’t enough info to provide any meaningful feedback.

UTG open is big, your 3bet is very big ... and he doesn't care. The 4bet size is "big" but not all in, all of which lean him towards AA and maybe KK.

Also not sure what "euro reg." means ... but the sizings do NOT imply he plays mostly online to me.

Shove or fold but lean heavily towards fold, unless you run good or you think he's 4betting super wide.

I would think in a live 1/2 when someone 4 bets its KK/AA but you would know this about your game much better than us. AK vs a range of AK,KK,AA,QQ is 39.5%, take out QQ and you're 37.8%, take out AK and you're 19.6%. Hypothetically even if he 4b say AQ/AJ he probably wouldn't 4b it at the same frequency he would AA/KK, so to jam this you would need to be confident he 4bs AJ/AQ 100% of the time. Easy fold.

Euro reg to me means he's aggressive and knows what he's doing. He raised from UTG and then 4bet. It's a fold unless there is some meta-game going on between the two of you or unless he sees you as a maniac whale.

You think he wouldn’t 4b QQ/AK? As a fellow reg, I would too.

He might, but we're not looking great against a range of QQ/AK/KK/AA, and I don't think he's folding.

Can he have AK? Sure, why not. But it's still not a good spot at 1-2. V really needs to have A5s for bluffs or AQ "for value" before it's more than a game of chicken.

Having shoved AK into KK+ more than most people at live 1-2, and won roughly 0% of the time, I fold a decent amount of the time now instead.

Again: preflop open is big, H's 3bet is big and 4bet is still big but not shove ... maybe that is AK sometimes, but in my experience it's AA pure. To be fair with the sizes, I'd expect to see AK a lot more than JJ.

Would be much happier if this was 2-5, so if "euro reg." means he's playing like that, then sure shove it and hope. As the saying goes "how bad can it be".