hi what's up.
your problem may well be that there is just not enough targeted inventory for those pages. - And maybe mediapartners got desparate and looked for contextual stuff from other parts of your site.
We know ourselves that PPC does not yet attract a lot of very niche advertisers yet, as when we advertise our own consulting services in Adwords, we almost have nil competition. i think this will change but in the meantime im happy to deliver kimono ads than nothing!
There's only a few serious Japanese marketing English language sites and services that use online advertising, let alone PPC - as we speak I could count them on the fingers of one hand
Similarly our info site has pages on Japanese, korean and chinese business practices and sometimes they often have "business" type ads but there are many kimono, japanese art, type ads. Peronally it does not worry me at all, as i think it is 1) likely that people interested in Japanese business may also be interested in Japanese culture and be "Asiaphile" enough to be interested in buying those items in some cases and 2) some people may go those pages from Search engines, who may well indded be more interested in buying kimonoes.
Similalry, people interested in using broadband internet to promote Australia to the Japanese may also be redisposed to these ads if they have an interest in Japan and want to learn about their culture as an aid to making their boradband services better..
Heck if it advertised a sushi delivery service in Bangkok right now given how hungry i am, i might even be tempted to click myself! (or at least copy the link, delete the id info, and paste in the address bar ;))