How do you find the contact info of a professor in a foreign country?
Some options:


Use a general contact for the university, either phone or email, and try to get specific contact information for the person.  I would expect most universities that deal with international students to be able to respond in English.  Try an international student office if you don't have luck with the main number (it doesn't matter too much that you reach the "right person"; as long as they are relatively helpful, they can probably easily access an internal directory for you).
See if the author has a profile on a professional networking site such as LinkedIn or ResearchGate.
Try to contact co-authors if there are any.
Use Google site search.  e.g. site:www.chikushi.ac.jp Yohei Kawajiri. If there was something in English, but hard to navigate to, this would probably find it.  Also should work for non-English sites that use Latin characters.  It didn't work in this case, though.