TT question

Apologies if this has a very simple answer, often simple stuff like this comes up and goes completely over my head...

In TT, when you have the "three open" rule in effect, is there any way to know which three of your cards are the ones visible to your opponent?

Often find myself trying to plan out some super sneaky move with one card and keep wondering does my opp even know I have this card lol

No, you don't know. (Which is a shame.)

Edit: Unless it's the 3 in the same position? Has anyone tested that?

Seems to be 3 random cards.