[sean457j]

I don't play any where near this buyin level, but here's what I think.

When ever I see four cards of the same suit on the board, unless I have the nuts or near nuts, I am desperate to check it down. The only bet I can see him making is with the Jd, and as you say he probably would have bet that on the turn. If you bet the river - which leads to a fold - then in the future you can make the same play again when you don't hit anything - knowing that a small river bet on a four suited board is probably going to cause the other player to fold (after he checks a possible completed flush). You may be able to start defining what value bets he will call/fold on the river against you, and with what type of hands.