Hmmm weird raise on river...

I can't imagine him having any bigger sets. 99 would have 3bet preflop most of the time, if he flatted, I'd expect him to raise flop or turn due to flush draws being out there... 55 would raise turn I'd imagine if he decided to call flop... He wouldn't get to the river with 66...

As for 2 pair, A9 would have raised flop/turn, same for A4 (We block though). A5 / A6 with possibly the Ah (nut blocker) could play this way but I doubt it, no worse hands would call river raise

Backdoor hearts gets there so maybe a pair and hearts called flop.. 9xh? Or Khx as a float? Your range is quite wide on the BTN so villain might not be too worried about the A out there

78 of spades is a possibility too. Flush draw on the flop and then hit backdoor nut straight

As for your small sizing inducing a raise, that could definitely be something to consider. He could be representing the flush but that would take a lot of balls at 10NL! It's rarely a bluff from my experience... That being said, it's hard to put him on a hand...

Ahhhh I would just sigh fold due to the population read of no players are bluff raising the river at these limits Interested to hear what others think

I like your play up to the river. I'm not sure why you'd want to go tiny unless it was for the purpose of inducing a raise. I would have gone ~$1.80 on the river to get value out of any top pair or 2 pair that hasn't raised. Once you're raised there are definitely value hands that have you beat like 8s7s or 8h7h as well as some backdoor flushes but there are also missed spade draws and random spazzes that should make this a call.

Why is no-one mentioning simply AhXh.... Seems like it makes the most sense to me.

Villain is not bluffing much here. Certainly not enough for us to call if they are any mind of thinking player.

A6 might get you out of jail some of the time but just not enough. Sigh fold and curse I didn't bet bigger to avoid having a decision facing the raise and missing value from his calling range.

I agree with @CrazyCookie the most likely hand here is the AHxH combos and that makes complete sense. Would bet fold also even though it is not easy to do.

That's a very ugly runout. Think I like the bet/fold line most, but I'd make it big, around 20BB. It kinda sucks to bet/fold a set on the river though, but I think we're rarely going to be good once we get raised here.

basically it is all said above. pre, flop/turn are std and good. river you just want to go big. you have quite a lot AX 2 pair combos, sets, bd hearts and some busted spades, plus your range is uncapped, villains is capped, so our range wants to bet big for sure. would say ~1.80$ to 2$ is fine.
people on 10nl just hate to fold top pairs BlindsvsBTN and they obv never fold 2 pair; villains will have a lot of each, so why not take his ass to value town?
when we get raised, we have to build a range that has enough bluff combos, that we can still call. in this particular spot, no villain on 10nl will ever value raise worse, so he has to have a certain amount of complete airballs, which is, for sure, just not going to happen

conclusion: despite the tiny river size, your hand was played fine.

Thanks a bunch guys, this was a ton of great insight and valuable information! I regret my tiny bet the second I made it and after I saw him tanking I though oooh here it comes...
Thanks for taking the time to respond, this helps me out in a bunch of similar spots! Cheers!

I'm not sure if i do fold river.
If we have him on AhXh, it has to be A6-A9 really - who doesn't 3bet ATs+ vs a btn steal? or indeed Lowball connected suited aces?
I think you can interpret your small bet to be a scared Ace, or a missed flush draw; or a set showing weakness, or a scared two pair.
I think straights are actually more of a possibility, and hands that were gutshots that got there backdoor...
For that reason, i think versus a thinking player i would make the call, because if i was sitting there with shit, (and this obviously applies more when there are stats that we don't know involved) i would be inclined to X/R the river after you show weakness. When you don't check it back it is obvious you have something that you are super sure of and could be a good spot to exploit.
Worth thinking about; Still think V can show up with a lot of value hands here too; i would definitely give this one a lot of thought.

10nl... Fd gets there.... Villain check raises otr.... Like bluffs are not a thing here. No one I have ever seen at 10nl is check raise bluffing rivers. Neither at 25nl and very rarely at 50nl. This is only close because he might do this with some two pairs but I even doubt it.

Did OP call?

^ The only reason i do think in game i cry fold. Thinking inversely... very strong move to pull off at these stakes if you are Villain.

chk/r bluff river after flush hits at nl10 - not happening enough to make me think about it, it's value.

XYhh or 99 3betting preflop OOP, doesn't happen nearly as often as one might think imo.

Neither does this the raise from villain in this spot, unfortunately I don't know if I could make the disciplined fold in game, but I'm fairly sure it should be a fold.

Basically it's a river spot where value is not quite thin enough that we should be using such a small sizing. So we can bet larger on the river and more comfortably play bet/fold as a result.

Due to population tendencies of rarely seeing worse hands than flushes x/r, it's probably an exploitative fold, although still pretty marginal overall, and not outside the realms of belief that he may mistakenly raise a worse hand for value.

Anyway, if we tweak the river sizing, most of our problems get solved.