A9s 4-bet bluff

Check it. You tried already twice to steal. It should be clear villain won't fold his hand most of the time

If we bet turn, we should bet river too. Otherwise just x turn.

Delay c-bet works best versus known opponents (that know you), and they need to have seen you check back strong hands on the flop as well for it to work well. Here is probably better to c-bet on the flop (if at all) because your hand is kind of face up.

As played, there is no way a river barrel is going to work often enough.

omg, hero What Are you doing? You have no hands vs unknown opponent and made 4bet bluff preflop? For what? Fold equity? Does your opponent have high f4b (52 hands is not eniugh)? Ok, what is the plan if your opponent call? Most probably you should give up. But you decided to overplay yourself.
Regarding how it is played. Check in position in 4b pot seems pretty weak, there is nothing scared on the board to push out your opponnent, only if he has AQ and AK you could try to steal steal it. So, if you decided to play and pushout op-t on post flop - you need just bet-bet-bet. But do you really think you Laggy opponent will fold AKs with VPIP: 28.00, PFR: 26.00? If there is a probability less then 50% - you just burning money.:f_biggrin:

just to note, your opponent could not only have AK-AQ, sometimes he calls 4b OOP vs regular with premium hands JJ+. So, you probably could make me folding JJ - I'm nit. But regarding this guy - not sure.

This is just a spew against unknow, but if you gonna 4b pre, for god sakes bet the flop, you're repping nutted hands to a unknown pre, do you check back KK+ against unknown on that flop as a standard? really? You say you think his range is TT-QQ then why on earth would you check the flop? None of this makes any sense, on turn you have no credibility and not on river either after checking flop.

I'm not sure we should be 4bet bluffing that much vs unknown but if you do so, I think it is best to bet the flop and give up. Since villain checked turn too and appears weak, it is ok to stab but stab river too. Single bet OTT will get too many calls from draws and smaller pocket pairs and those will fold to a river bet.