Here's the spot:
https://sunshinecity.jp/en/observatory/enjoy/
Look for the guy with a beard & a purple shirt in the green hilly area.
Entry costs 700 yen for adults.
https://sunshinecity.jp/en/observatory/ticket/#anc_someDayTicket
Location & Directions: https://sunshinecity.jp/en/observatory/access/
Accessibility: https://sunshinecity-jp.translate.goog/file/official/barrierfree/other.html?_x_tr_sl=ja&_x_tr_tl=en&_x_tr_hl=ja