I think so. You lose to the A, K, Q and 9 of diamonds (the latter a straight flush), I dont think, any worse hand check-jam for value, and the average population is not bluffing much at all with a line like this on a 4-flush board. The turn could be checked back also.
You study this by looking at Villains possible hand combos-
1 how many value combos compared to your hand?- Ad...how many combos? Kd...Qd...9d...
2 Value that we beat 5d 4d 3d 2d-- would they jam when you bet?
3 How many bluffs? Is there any on this board? Why would this player turn a low flush into a bluff--meaning they have the 5d and are trying to get you to fold Jd Qd Kd- some players might-- would this player is our study point--what data do we have from playing vs this player that would suggest this player would do that.
4 We use math to figure out how many bluffs they have to have -what %- for us to call.
Study how to do that. If they only bluff 10% of the time we cannot call for instance.
