Richard, while I'm sure you posted that with the best of intentions, I don't know if that really helps the OP. I have personally been to Otaru five times and have been kicked out of zero establishments (and I am painfully white*). In fact, throughout four years in Japan I was denied entry to a private business (and this includes many, many onsen) exactly once, and that was a club in Sasebo specifically for JMSDF officers and chief petty officers which most Japanese wouldn't be able to get into (at the time I didn't read enough Japanese to know what the place was).

Not to belabor this but I would enourage the OP not to worry too much about what Mr. Aldwinckle says at the link. There are absolutely businesses in Japan that won't let foreigners in, but at least in my experience smiling and being polite will work wonders for you in the vast majority of situations.

That said, I know RichardInSF and many other people may have had far different experiences than I have had, and I'm sure someone out there is going to disagree with me, so I would encourage that discussion via separate thread, PM, or OMNI.

*Disclaimer: This is my attempt at humorous self-deprecation, nothing more.