V1 is BB ~$350
Hero is MP ~$750

1/2 NL, have been playing pretty standard but recently (last 1-2 hours) have shown down some goofy hands for massive pots (stacked a guy with KdKx with 6d9d on the turn of Qs8d10d5c...As for $650 pot) and open-raising most of the pots I play to $8-11. My image might be a loose aggressive young kid.

Villian is middle aged man, plays straightforward passive poker. I've bet him off several hands with cbets in the session and otherwise we haven't really gotten involved much.

UTG limps $2
Hero Raises to $9 with As9s
Villian calls $9 from BB
UTG calls $9

Pot: $28

Flop 6s6c9h

Villian donks $12
UTG folds
Hero raises to $40
Villian calls fairly quickly

Pot: $108

Turn 6s6c9hKh

Villian checks
Hero checks

I'm putting Villian on a 9 as well, figuring I can likely get one more street of value when he thinks he's likely chopping thanks to the King.

River 6s6c9hKh9c

Villians bets $77
Hero ???

Do you smooth call for showdown value or raise for thin value? I had some trouble deciding if I should min raise and hope to either chop, get called by a 6 or maybe a TT/JJ/Kx? But if villain 3 bets me I'm in a tough spot and he can do that with a 9 and force me out.

What do you think?

Raise. Most likely though he has the other 9.

How do you define "thin" value?

thin value betting is when you value bet with a medium strength hand (a hand much lower than the nuts, thinking you are ahead and villain will call you).

I really don't think this villain is donking out with a 9 and when he flats your raise this confirms it, from a straight forward middle aged passive guy on a paired board.

I would think it leans more towards over pairs

Surely this type of villain raises KK pre flop and if he has quads unlucky. I'd be raising an amount you'd think the six would call and calling off a reraise expecting a split pot. K9 would be upsetting but that wouldn't deter me.

Raise to $175.
Puke and call if he shoves.

People will de stupid things with 6X here.

Zeebo theorem; raise big.

There is $260 in the pot 'when' you call. He 'only' has $225 behind ... What's he going to call with?

6x boat ... Really doubt V as desribed is calling a River raise with 6x, but I also doubt he would lead out either ... really? What does he put Hero on and why didn't he continue on the Turn? 6x really doesnt make sense unless he wanted to c/r the Turn .. and you smartly didn't give him the opportunity to do so. This could be a blocking bet, but you arent getting anymore chips from him here with 6x once Hero checks Turn.

9x boat ... Obv chop here ... Who's going to fold? No one.

9K boat ... Uh, yeah, my radar always goes up when an older man (anyone over 35 for poker!!) donks the Flop and checks the Turn when an 'obvious' old-man card hits the board and then re-donks the River with a goofy number.

KK boat ... Same thing with check on the Turn, although he wouldnt c/r here I would expect a fair share of c/c (of course).

I just don't see 6x calling you down and there are more combinations of hand that beat you than you beat that call a raise. Flat and showdown .. GL

There are 6 combos of all hands that beat us (3 x KK and 3 x K9).
There are 6 combos of K6 alone.
So, if we think that he can get froggy here with K6 (as it's better than a naked 6) then we can't fold here.

If we think that he won't get weird here with K6 then we can just call here I suppose.

Question was aimed toward OP because he's calling this a thin spot.

Call flop. Raise river.

V can pretty much only have two Kx combos here, Kd6d or Kc9c. Don't think an mawg is calling with K(6/9)os. At the very least, heavily discount the offsuit combos. KK is 3 combos. Sounds like he's way overvaluing something like A6 though. imo it's more likely he's calling A6os than any offsuit K. He's far more likely to have AK or KQ, maybe even KJ, than any combos that beat you. But like irtm said, raise and call off a shove.

Im with R Parker. This isnt a thin value spot, its Phat. Raise it 100. Call a shove. NEVER fold this. K9 is the only hand I see beating you (unlikely he plays K6 for a raise and KK would've surely 3!).

This is actually exactly what happened, old man actually woke up with 66 for flopped quads. His weak lead on the flop didn't even put that hand on the radar for me. I was more convinced he had K9 or a chopped pot.

I called it a thin spot because I thought I could get a min-raise call if he had tried to slow play the 6, but was also likely to be chopping, or rarely losing. Am I using that incorrectly?

After the hand (and I lost so of course I'm thinking about it) I was wondering if I should've just flatted the river because of the odds of him calling with worse were bad, but raising with a chop or winner are higher. I think in the end it was just a cooler and I moved on.

It doesn't have to be a medium strength hand. It just means that if your opponent doesn't fold, the number of hands you beat is only slightly more than the number of hands that beat you. You could have the second nuts and this could be true, such as when you have the second nut flush and you think raising all-in will get you action from only slightly more worse flushes than there are hands that give your opponent the nut flush.

As described, villain seems like a fit-or-fold passive player who will either b/f, c/c, or c/f 6x hands. He also seems like the sort who will think hero has 9x here always, even if he thinks hero is a young LAG. I'd go with that read until I see him play a hand which directly contradicts that read.

I see similar passive players who will fold and show 6x against me after they check the river and I bet and wonder if they folded because they think I am tight and respect my bets, but then I usually see them do the exact same thing if a similar spot pops up against the LAGgiest LAG at the table, so I realize they are usually just playing their cards and not the player.

A river raise is mostly for show, since Villain looks like he has TT/JJ/QQ, and he's rarely calling the raise. If Villain reraises, I'm calling.

Wow I read the post and just thought easy call vs described Villian. I wouldn't have even thought about raising here as I'm never really getting called with anything less than a 9 and some combos out there beat me. But lots of people are advocating a raise here so that makes me think I need to rethink my thought process.

I'm tending to think if this situation happened again I would lean towards flatting the bet, because like Macktyson is pointing out, what worse hands are calling my raise here? And several ties/better hands are raising and putting me in a tough spot.

It's a call against some villains and a raise against other villains. (Table image may also play a role.) If you want to analyze your thought process, you should be thinking about what villain tendencies lead to option 1 and which villain tendencies lead to option 2.

Basically, you should never raise a player who is always folding 6x or worse to a raise. Players like that do exist. The question is, should that be the default assumption or not?