This is quite interesting re. Japanese users tending to score lower than Western users, in part due to wanting to encourage kaizen (improvement) and giving 5 stars doesn't leave any room for improvement, in part because they may not want to give away the really good spots to eat, but also because "Japanese survey respondents in general exhibit a “central tendency bias” — an inclination to choose a middle category and avoid extreme opinions".
On Japan's top foodie site, imperfection is gold - The Japan Times
https://www.japantimes.co.jp/life/2025/03/09/food-drink/tabelog-ratings-cultural-influences/