"Hey there, you can call me Mike"

Now, I'm no expert so people with more knowledge on how it looks in Asia might be able to correct me, but as far as I know it is common in Hong Kong and Singapore that ethnic Chinese people take an official western first name and go by that. It seems like that in Taiwan, quite a few people take a western name that they use in an International context but do not have this name registered officially. As far as I know, most other countries in Asia do not follow this and do not use western names at all, including Japan.

But yeah, whatever, my expertise is not in other Asian countries in any case, but the above is the image I have from my (mostly professional) interaction with people from the other countries in Asian. But what I want to get through here is very simply that Japanese people do not use Western first names unless there's a very good reason for it (e.g. foreign parent, born and grown up overseas or such). So if you encounter "Benny Takegawa" you can feel quite sure that he's either Japanese-american or have some foreign heritage (I would for instance also be a prime example here as I have a western first name and a Japanese family name I use in work).

Or, at least, that's the basic rule... On a few occasions I have run into completely Japanese people who have had a normal business card on the Japanese side, but on the English side they have had written in quotation marks a Western name. In my mind it creates this huge distortion between a 100% Japanese guy who's named "Masahiro Kitaguchi" and seeing the name "Mike" in quotation marks between the two Japanese names.

Once I actually asked the person why he had a western name in quotation marks and he admitted a bit embarrassed that some people from the head office had given him that name since they found his real name too difficult to pronounce and write...

I find this ridicilous and mildly-offensive since there are other ways to give someone a nickname; shorten the name or something else in the vicinity of the real name, rather than just randomly assign someone a western name... I have yet to encounter any foreigner with "Michael "Masahiro" Smith" written on his business card, for some reason...

Source: http://foreignsalaryman.blogspot.com/2010/08/hey-there-you-can-call-me-mike.html