Best Traditional Japanese-style Breakfast in SF?
Not so easy. The only one I know of -- and I haven't checked the Japanese-owned hotels -- is in Union Square on O'Farrell, south side of the street: Dojima-an. Simple decor, simple service, almost diner-style. Only OK quality, but good enough if you need Japanese breakfast, as I recall.
219 Ofarrell St, San Francisco, CA 94102