Semibluff, then fold to a river bet?

[bjarne]

Hmm, I gave a long thought to this yesterday and I start
to see now why check/calling > bet/fold in this case and how
I've been playing some of these situations wrongly.

So for this specific example I've now changed my mind to

check/fold > check/call > bet/fold

I have another question now though,
Knowing that opponent is passive as in this case (0.4!) would it have been better to check/call the turn instead of continuing the semibluff.

If you check the turn and opponent checks behind you get a free card and can take the check/call or bet/fold route on the river since he showed no strength on the turn.

If you check and he bets you can safely fold the river UI.

Or is betting out the turn still correct?