You don't have any choice on the river except to get your chips in. Maybe check and hope your opponent bets... but your chips are going in. (I say you'd rather have your opponent bet because he will bet with more hands that you can beat then he will call with that you can beat)

If you honestly think that folding a 35,000 pot for a 5,000 bet on the river with top set is ever a good play without your oponent accidentily exposing his cards, you're a far better man then I.

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-You may not know this, but poker is a game of incomplete information.