Fold two pair on the river?
 

Should I have check/called the river instead?
I tried the value bet, but as he raised I was sure he had either the straight or the flush.
My thinking was, that he would have raised the turn instead if he was bluffing, but whenever I find my self calling such river raises I'm toast.

Party Poker 0.5/1 Hold'em (10 handed) converter

Preflop: Hero is BB with 5[img]/images/graemlins/heart.gif[/img], 7[img]/images/graemlins/club.gif[/img]. MP1 posts a blind of $0.5.
<font color="#666666">3 folds</font>, MP1 (poster) checks, MP2 calls, <font color="#666666">3 folds</font>, SB completes, Hero checks.

Flop: (4 SB) 5[img]/images/graemlins/spade.gif[/img], 7[img]/images/graemlins/diamond.gif[/img], 3[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(4 players)</font>
SB checks, <font color="#CC3333">Hero bets</font>, MP1 folds, MP2 calls, SB folds.

Turn: (3 BB) 4[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets</font>, MP2 calls.

River: (5 BB) K[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets</font>, <font color="#CC3333">MP2 raises</font>, Hero folds.

Final Pot: 8 BB

Re: Fold two pair on the river?
 

I'm calling. I think it's just as likely to be someone calling down w/overs incorrectly who spiked a K as some sort of slowplay. But I'm not raising.

-Jaran

Re: Fold two pair on the river?
 

I think this is a pretty bad fold at $.50/$1. When it comes back raised on the river you're getting 8:1, which means if he's raising a naked K 11% of the time you're making a profitable call.

Most players at this level will raise the straight or flush when they make it on the turn. (Some will wait for the river if they have a weak flush, but it's not typical IMO.)

Sure, you're beat a lot of the time here, but not enough to make a call -EV.

Re: Fold two pair on the river?
 

I think check calling this river would be a mistake. You are most likely ahead here. As others pointed out, most players would have raised you on the turn with a made straight or flush. Value betting was a good idea since your opponent would have likely called with a weak made hand that wasn't worth a bet. If you check he will mostly bet hands that have you beat. This is important, most of your opponents at 0.5/1 call too much, and you have to exploit this weakness.

Bet/folding this river is a big mistake. You are given 8-1 on you're call! Your opponent might have spiked a K and decided that it was worth a raise. Maybe he had overcards with 1 diamond and is bluffing a busted draw. You only need to be good 11% of the time here, and I think you will win much more that.

Re: Fold two pair on the river?
 

I think this is a terribly weak laydown.