Hi Gav,
What an absolutely breathtaking knife!!! and while I dont know a great deal on these, I thought I'd add a few notes while we await the usual stampede to express opinions and observations!!
I think the most difficult weapons to identify must surely be Korean, as they really dont adhere to set patterns and reflect mostly styles of the Chinese as well as the Japanese who occupied them from 1910-45. Most of the heirloom weaponry was destroyed to eradicate and subjugate the culture from what I understand, but certainly examples remain.
In this piece, profound Chinese influence of the Manchu's Qing dynasty prevail. The scabbard and its mounts are of the typical yuan shi qiao (rounded end scabbard) common to late 18th throughout the 19th century in China. These are seen on many of the remounted sabres with goose quill and willow leaf style blades.
The pommel cap reminds me of the hats worn by Manchu's and it seems of a style (commonly termed horses hoof) seen on the familiar sabres with 'oxtail' blades so commonly seen after the Boxer Rebellion. The quatrefoil style guard is seen also on a number of these oxtail swords, but it seems those are not solid piece like this.
The red lacquering on the scabbard is also often seen on these Chinese scabbards.
It does seem that in some conversation long ago I was told Koreans had a particular affinity for applying red to thier swords. Naturally since I cannot substantiate that, it remains simply a curiosity aroused by seeing this piece.
What is most unusual and attractive is the Japanese style blade resembling those loosely in profile, and the very decorative habaki (blade collar).
It would seem as noted, difficult, to classify this as distinctly Korean, but seems very plausible with the combining of element influences in the reflective culture of Korea. I wish there was more research material or resources on Korean items, but even the single article ever written on them by J. Boots in 1934, does not address much on general identification, only early history mostly.
All the best,
Jim