Hello,
Just a few thoughts regarding the Dao of the original posting.
While the condition of the blade makes very difficult to have a positive ID, I am inclined to believe this is an imported Japanese blade.
The fuller, both in shape and position, is also quite typical "bo-hi" of the Japanese blades.
During the late 16th century, Japanese blades (mostly mass produced) were heavily traded with China and Korea and many ended up with in Chinese and Korean mounts. And I think this is one of them.
