the roof of the Kōshien Stadium

(dated) Mount Rainier (a mountain in Washington, United States)

(figuratively) cheap; of little worth

Mount Tsurugi in Tokushima prefecture

(linguistics, uncommon) trigrade conjugation / (informal) 3-step process

participate in / take part in / join / attend

one day, 24 hours / the daytime, the period from dawn until dusk / (figuratively) a short period of time / one day, someday, an unspecified day / the first day of the month

(literally) one side / everywhere, all around, the whole area / one viewpoint, one opinion or way of thinking / the front page of a newspaper

for the time being, for the present

the basics, a general idea