that's a bold statement. Google does notice that when they see some link network get too big. or maybe they have honey pots and they consider your server hacked if they see your pages linking to that honey pot.

but thinking they know when a server if hacked is giving them too much credit. they may know when it's part of a widely know black link network. in fact, most search engines seems to know that.

reason your links are for Japanese sites is because there everyone uses the cellphone operator default search, which is crappy, but still better than Google for native language. they may be slower to react or worse at detecting black link networks.

disclaimer: i work for one of the biggest western search sites in Japan. but this is my opinion.