There is a whole parallel smiley history from Asia that either hasn't been documented as well as the western smileys or simply hasn't been translated.
The notable thing about asian smileys is that they have the same horizon as the text, whereas western smileys needs to be turned 90 degrees. Compare (^.^) with :-)
So given that ¯\_(ツ)_/¯ is both unicode and horizontal indicates that it is either from Asia or came to be after asian smileys became more prevalent in the west.
Interesting that Japanese smileys show emotion via the eyes while the American-born ones show emotion via the mouth, which mirrors the respective cultural norms.
Probably Japan. ツ is a very common Japanese charterer pronounced "tsu".
As wodenokoto said there is a whole separate history of Asian smileys that are right way up, with the face in the middle and various decorations on both sides. They did have the advantage of a larger set of characters from the start.