emaureeng:

4.  I Hear Your Voice - the ML reads minds if he can see someone's eyes. The FL is one of the few people he has told about this.

Sorry, I'm  looking more for communication between  the characters, or at least  an active role by one character in interpreting the communication of the other character.  In your case, if I understand it right, the FL knows about  the ML's ability, but  doesn't seem to have any other role. 

 hayaka:

Sorry, I'm  looking more for communication between  the characters, or at least  an active role by one character in interpreting the communication of the other character.  In your case, if I understand it right, the FL knows about  the ML's ability, but  doesn't seem to have any other role. 

Actually I just watched a clip of this and the ML does communicate with the FL, telling her in court what the witness  is  thinking through non-verbal signals.  So I can accept this one.  :)  

5. Snowdrop(FL and ML,  knocking in a way that only the two of them know)

6. Jirisan (using sticks and stones to indicate mountain locations)

7. Bad Buddy - As kids (then again once that we see as adults) they used the tin can and string telephone to chat. Let me know if that counts.

8. Hyde, Jekyll, Me - Well this one is interesting b/c of how the 'three' main characters communicate. 2 cannot do so directly, so the go via computer video messages or via the FL. - Again let me know if this one counts.

9. Love and Leaches (ML wears glasses as a sign that he is in a BDSM relationship with the FL. They have a code too, which is the name of the mascot of their company)

 newbiefan:

7. Bad Buddy - As kids (then again once that we see as adults) they used the tin can and string telephone to chat. Let me know if that counts.

8. Hyde, Jekyll, Me - Well this one is interesting b/c of how the 'three' main characters communicate. 2 cannot do so directly, so the go via computer video messages or via the FL. - Again let me know if this one counts.

The can and string definitely counts.  On the other one,  if it's just email or the equivalent then no, but if a 3rd party saw the video and wouldn't know there's a message embedded (i.e it's personal to them) then that's fine. 

 Bong Bong:

9. Love and Leaches (ML wears glasses as a sign that he is in a BDSM relationship with the FL. They have a code too, which is the name of the mascot of their company)

mm.  The glasses, I don't think so.  Not really what I was looking for. As for the mascot, do they have an actual code that is derived from the mascot, or does it just have a single symbolic meaning for them? 

 Bong Bong:

9. Love and Leaches (ML wears glasses as a sign that he is in a BDSM relationship with the FL. They have a code too, which is the name of the mascot of their company)

Also, Love and Leaches is a movie, not a drama.  

 hayaka:

The can and string definitely counts.  On the other one,  if it's just email or the equivalent then no, but if a 3rd party saw the video and wouldn't know there's a message embedded (i.e it's personal to them) then that's fine. 

Um, very few people know of their communication as very few people know that it is two personalities in one body. The FL might know of it (cannot remember).

How about we discount it. 

Next to post continues with 8.

8. The Lost Tomb series - Wu Xie and Zhang Qiling have secret codes by knocking (something like morse code)

9.  Rooftop Prince:  After he returns to  Joseon at the end of the drama, the ML leaves letters in special places that only the FL can find, hundreds of years later.  It's actually kind of heartbreaking, as the ML writes the letters knowing he will never see or hear from the FL again

10. Police University(https://www.youtube.com/watch?v=wrKhKYujPfQ)


10 dramas where the FL says the ML belongs to her or something similar("He is mine" or "He is taken))

1. Weightlifting Kim Bok Joo - FL yelled to flirty girls that the ML was her boyfriend (does this count)