Help ID this Japanese (?) frameset.
 

Hey folks.
I picked this up for cheap a little while back. I am assuming it is Japanese in origin because of the Tange dropouts, 26.8 seatpost diameter and overall appearance. It measures 62cm c-c on the seat tube and 57cm c-c on the top tube. You'll notice there are no eyelets and the geometry is quite tight, perhaps indicating a racing frame of some designation. And no, the area with the missing paint is not where somebody has hacked off downtube braze-ons (thankfully).
The serial number, 00600, is puzzling me the most. I've never seen such a format before.

http://farm3.static.flickr.com/2699/...1263a390_o.jpg
http://farm3.static.flickr.com/2500/...5ecfb7fb_o.jpg
http://farm3.static.flickr.com/2742/...007de74b_o.jpg
http://farm3.static.flickr.com/2610/...b633dea6_o.jpg
http://farm3.static.flickr.com/2645/...bd71e59a_o.jpg
http://farm3.static.flickr.com/2622/...b86655ef_o.jpg

Any ideas?

Panasonic maybe?
 

I've got an '85 Touring Deluxe that looks exactly like that except it has canti bosses on it. Usually Panasonics have serial #'s on the headlugs, though...

Oh come on, is that it!?
Thanks for your input cannonedge.

I think traffic has been light since the website has been experiencing problems. Sorry I don't have any idea about the frame.

Really it was my first reaction too. Yours has steep angles, not a tourer. what is it ? A 60cm or so ? Checking the stay lengths against the Miyata etc. , you'll verify it's aggressive angles. 26.8 seat post diam., I don't think it's hitens, besides, old race geom. bikes weren't hitens for the most (very) part. It's no Miyata. Nishiki, I don't think so.
A whole bunch of brands that it most likely is not so I'll save it.
Panasonic, the very best and only one that could be considered had 4130, all Panasonics did tthat had chromoly so it makes little sense that they would have Tange dropouts and not advertise Tange tubing, possible, not likely as far as I suppose.
This is ALL deduction, how could it be anything else ? I checked threads here; the short version: Ser. #'s are all over the place. There was one or two fellows, owners that I spotted, submitted 4 or 5 digit #'s. The rest had a letter or two preceeding 4 numerals, the 0 could be an o..... whatever. Just shows that it or anything's possible.
Having seen a bike with embelished NON Japanese style, fancy lugs, I'll never forget. I saw two; one up close in real life and one on e-bay, both were orange, both were 1976 Centurions. The brand was all but unknown to me 'till 24 years ago, not big in NYC 'till that point in time, Cents. have eluded me. The ones I saw were only 2 and 3 years ago. BOTH had chrome lugs and that bussiness at the head tube, the curvatures etc.
Yours may've been painted over, maybe never painted. Cent. was much more well know for its hitens bikes prior to the '80s by most accounts. I'm no expert, I just remember things and am just as often wrong as right . Scrape a little for curiosity for chrome. Aside from the chrome lug feature, the Cents. including the one I was nosy with had paint on chrome. not all Co.s did that. Miyata as you know used an electrostaic coating under the primer coat(s) , under the base coat(s). Cent. and a couple(few) others used chrome, darn near show finish. It's all I got. Google it as 75, 76 to see at least one white one.

Thanks for the input guys.
Old and new: It's a 62cmX57cm frame. Yeah, it's definitely no Miyata or Nishiki, as I know them very well. No to Kuwahara too.
I was thinking something like a Panasonic, but like you said, this is pure speculation/guesswork.
I'm in Australia, and I picked it up over here, so even though that doesn't really narrow it down, perhaps it suggests it's a locally-branded frame, built in Japan and then sold by one of the myriad of shops/brands back in the day under their own name.
I can't tell for sure if it's been repainted or not, but I don't see any evidence of stickers/decals, so I think I'll say it has.