While Japan once again tops this year's Times Higher Education Asia University Rankings, it is finding its traditional dominance in higher education increasingly challenged by China and South Korea, education experts say.

Japan held on to the No. 1 spot in this year's rankings, released Thursday, with 20 schools listed in the top 100, but China now has 18 of its mainland institutions listed. And if six schools separately listed under Hong Kong, Beijing's special administrative region, were included, China would lead the list with 24.

South Korea came in third, with 14 institutions listed, while Taiwan fell from second to fourth with 13 schools in the top 100.