On Sep 26, in an article titled "東京五輪メダル候補 卓球王子 水谷準選手の“禁じられた恋”の話", tabloid magazine Josei7 gives a detailed account of Mizutani's extramarital affair with then underage Emi-san(19, pseudonym).
https://www.news-postseven.com/archives/20190926_1457718.html
Gist of the article:
An acquaintance...