Here’s some agricultural news. Since the article says that truffles grow wild in Japan, I was curious to find out what they are called here. The only Japanese name I could find was the katakana for truffle: トリュフ
https://academist-cf.com/journal/?p=2717
I found a couple of other academic articles
https://www.jstor.org/stable/23055170?seq=1#page_scan_tab_contents https://www.jstage.jst.go.jp/article/msj7abst/61/0/61_19/_pdf
but as far as I can tell, truffles of this type have not been part of traditional Japanese cuisine.
– Kirk