Hand happened on betcoin, a bitcoin poker site. 500NL

Villain is a reg, plays solid tag style in 6max and FR. About 20 mins into the HU session no significant showdowns and pots have all been small-mid size, he seems to be trying to grind me out.

Hero picks up AA on the button, raises to 2.5x , villain calls.

Each started the hand with $750.

Flop($25): 974 rainbow. Villain checks, I bet $17, villain check raises to $50, I reraise to $140. Villain calls.

Turn($305): 974J. Check check

River($305): Hero bet $200, villain check raises all in. Hero???

i tanked and ended up folding and felt ok about it. Villain very likely had a set since it was his first check raise and he been trying to grind me out blahblahblah.
Although villain is definitely capable of turning A9 into a bluff here. I showed weakness by checking the turn and this is a golden spot to bluff given I can't call unless I had a set on the flop.

Thoughts and comments?

We certainly don't beat any of the hands in his value betting range given the way he has played. Only doubt is that this is such a good spot to check raise all in after I checked the turn. Reason for checking the turn was to get paid off on the river since A turn bet would look so strong and only 2 pair and alive would call.

i assume river is a blank?

call flop, fold river

betcoin, huh? I didn't know any bitcoin poker sites had any real action over 200NL.

And yeah, I like a flop flat instead of a 3bet.