You may well be correct. But I distinctly remember being told Tang Soo Do and Hapkido resisted coming under one controlling body. Unfortunately, since that was some 30 years ago, I don't remember the source. As to not being called Hapkido, I got the distinct impression it wasn't too long before I was told about it, that it had happened. Could there have been two attempts to bring all Korean MA under TKD?
It's not like people were going around kneecapping people if they didn't join...
The first unification movements was in (if memory serves) 1955. There were five Kwans involved: Moo Duk Kwan, Chang Mu Kwan, Chung Do Kwan, Jido Kwan and Song Mu Kwan. The Korean War kind of stalled this effort. After the war, these five were joined by the Oh Do Kwan (from which the ITF evolved), Jung Do Kwan Han Moo Kwan and Kang Duk Kwan.
Tang Soo Do was the style taught by the Moo Duk Kwan, so as one of the original five, it's pretty clear that they didn't resist anything.
GM Hwang Kee left the unification movement with (reportedly) about 1/3 of his Moo Duk Kwan students in about 1964 and resumed teaching Tang Soo Do for a few years before changing the name to Soo Bahk Do Moo Duk Kwan.
So you could say there were two movements, if you consider the Korean War to have halted efforts. Or one protracted movement, if it was only on the back burner for a while.
I don't known when the name "Hapkido" was first used for the art, but I have always understood that (like most systems...) it's had several evolutionary names. I did a quick check and the Korean Hapkido Association was registered in 1969, but that doesn't tell us when it was first used.
He would know I would guess since he was there at the time. As far as I know, I wasn't, since the first time I was there was about 74-76, then again in 79-81, and last from 84-87. The last time was when I studied Hapkido there. Do you remember the time frame your KJN talked about?
Well, GM Hwang left in (about) 1964, so that would be when the Moo Duk Kwan splintered into two groups: Moo Duk Kwan Taekwondo and Moo Duk Kwan Tang Soo Do. Other splinterings have occurred since then, obviously.
So Hapkido was never a part of the unification movement. Was this because there was no invitation to join, or because they declined the invitation? I don't think there's any way to know for sure, but I'm inclined to think there was never an invitation. Had there been one, it's likely that one or the other group would have recorded it.