The photo quality could be better, but it looks to me like it is a mid-range Japanese-made frame from the mid- to late-1980s. The rear dropouts are not stamped, so it's not a low-end frame, and the single shifter boss on the downtube is for unitized Shimano or Suntour shifters, like you can see on the bikes photographed in this thread.
It's hard to tell for certain just from what I see in the photos, but the lugs appeared to be thinned toward the ends, which is again not something you see on low-end frames.
If you ask this question in the Classic & Vintage sub-forum from which I linked the above thread, you'll likely get a quick and accurate answer. I wish I could tell you more, but I don't recognize the semi-wrapped seat stay lugwork, though I'd wager someone at BikeForums will know much more.