In Mark Bishop's Okinawan Karate (2nd edition, 1999) there is a short anecdote about Bushi Takemura/Tachimura who worked as a tax collector but was once attacked by a crowd.
Quote from this anecdote (p.139): "...his right foot would be seen to sweep up and scuff the head of an attacker who would run clutching his head in an attempt to replace a flap of skin and hair that had been removed by Takemura's extraordinary 'scalping kick'..." (This is said to have taken place around 1897.)
Since Takemura was a close friend of Sokon Matsumura I believe this is pretty much an early stage of Okinawan Karate.
I also heard that Seiken Shukumine of Gensei Ryu and Taido demonstrated Hachidan-tobi-geri in 1950 at a karate exhibition for Nippon Television. (I would like to see this demonstration, but haven't found footage.)