What do Japanese universities look for?

I am a high school senior interested in majoring in Japanese. I have already been accepted into several American universities, but am thinking about transferring into a Japanese one after my first semester (for April entry).

I would like to know what Japanese universities look for in international applicants. I assume that GPA holds the most weight in application decisions, but do they also care about extracurriculars, standardized test scores, English fluency, etc.? My GPA is not extremely competitive, but my standardized test scores and unique extracurriculars "balance" it out to some degree.

Also, do recommendation letters affect your application greatly? I have done some research about Waseda (SILS), Sophia (FLA), and Meiji (School of Global Japanese Studies) and noticed that Sophia and Meiji require recommendation letters...

I would appreciate any advice. Thank you in advance!

Like any university in the world, they are basically looking for 3 / 4 things
1) intelligence / good test scores
2) applicants should have a passion for the subject (i.e. understand what you're getting yourself into)
3) the ability to pay tuition and living expenses
(4) sufficient linguistic ability to deal with the course

It's basically that simple

In my experience, whilst required, recommendation letters have little influence. They can provide some context to an application, but they will never get you in.

I see, thank you for the answers!

I was not expecting them to get me in; I only wanted to see if they held a different level of "value" compared to the America's college admissions system!

Dainichi Heater summarized it well. We just would like to specify that you would need to be at least JLPT N2 to have a chance to be admitted (and/or take the EJU). FYI, most programs in Japanese Higher Education are only in Japanese indeed.

Now, to answer your question: most Japanese universities are looking for international students. Or at least, this is an objective nation-wide as the Japanese government is trying to appeal to international students (thus the "300,000 foreign students" plan which consists in almost doubling the number of foreign students by 2020, and the "Global 30" initiative which is trying to increase the number of programs in English in the universities).