Japan appears to be suffering from brain drain. Examples include chemist Osamu Shimomura and physicist Yoichiro Nambu, both of whom won Nobel Prizes in 2008 for research conducted in U.S. universities.
Japan is not the ideal place to seek employment for some postdoctoral researchers. According to a study conducted by Masako Asano of Osaka Prefecture University, 41 percent of postdocs in particle physics leave Japan to get jobs because there aren't enough here to go around.
But Japan's public universities rate quite well internationally, according to the evaluation committee on national universities, part of the education ministry.