Rather unfortunate... This map does not appear to look very much like Japan. Even worse, its so skinny that it would be difficult to put a city on it without it touching both sides. The map itself is far too straight and has quite a few outlying islands-it appears to look like a Hebridian peninsula rather than Japan. The actual Japan shape is much like a boomerang, with curved out ont the edges.
Its important to look at a map on what your making, to make sure that you are accurate.
The map isn't completely unusable, but frankly I don't know where it could go. It should best be treated as one section of Japan rather than Japan as a whole. A good scenario would possibly be one concerning the Ainu island at the top, as it is a bit wider, so travelling down one side of the coast no one would be able to tell the difference. I'm not sure if you should download this map, I'd say take a look if your interested.