Tough River Spot with TPTK

[RRiccio]

Seat 1 is the button
Total number of players : 9

Seat 1: Villain ( 45,684 )
Seat 5: Hero ( 43,415 )
Seat 7: Seat 7 ( 25,463 )
Seat 9: Seat 9 ( 19,433 )
Seat 2: Seat 2 ( 4,956 )
Seat 4: Seat 4 ( 14,076 )
Seat 10: Seat 10 ( 41,270 )
Seat 8: Seat 8 ( 13,983 )
Seat 3: Seat 3 ( 63,667 )

Level: 7
Blinds(300/600)

** Dealing down cards **
Dealt to Hero [ Kc Ac ]
Seat 4 folds
Hero raises [1,800]
Seat 7 folds
Seat 8 folds
Seat 9 folds
Seat 10 folds
Villain calls [1,800]
Seat 2 folds
Seat 3 folds

** Dealing Flop ** [ 8d, Js, Kh ]
Hero bets [3,500]
Villain calls [3,500]

** Dealing Turn ** [ Qh ]
Hero bets [7,200]
Villain calls [7,200]

** Dealing River ** [ 6c ]
Hero ?

Sorry, couldn't get to convert the hand on standard converters. Party must have messed up the hand histories again.

Tourney is Party's $13K Gtd Rebuy. Average was about 25k.

I'm not sure what's best on the river. Villain is a bit donkish. Should hero make a blocking bet, c/c or c/f?