Since around the 16th of this month all KWs in Japanese return a N/A. Now today KWs in alphabetic letters with the "Restrict Ranking To Single Language" to Japanese setting, also return a N/A. I tried different settings, but they all return a N/A.
Did you try it with the restrictions off? What's the keyword and URL specifically and where do you think it should rank when looking manually?
I tried with restrictions on or off and with with different combinations. Example: KW: シガー URL: www.cigarjapan.com 1+2 rank on www.google.co.jp
Hmmm... it looks like it might be a bug in Google's API. The results for the query look like it returns every page in Google index, so almost like it's being ignored, and just returning EVERYTHING. Odd...
Very odd indeed... I've just looked at an email I get from a google alert service which tracks the top 50 ranks for the KW シガー . According to them the 50 top ranks have all been replaced with Chinese-looking website titles that have nothing to do with the KW シガー. So I think that like you said, there is something wrong with what Google's API returns for a query on www.google.co.jp.