(Internet slang, especially anime and manga fandom) events or things from the past which one wants to whitewash/erase from history (due to it being embarrassing, poorly received, etc.); dark past

oral history

historicism

Japanese food, Japanese cuisine

Japanese foods, Japanese cuisine

Japanese-style painting - Japanese paintings based on Japonism

a Japanese sword

State of Japan (de facto official name of Japan, 1947 to present)

(rare) State of Japan (de facto official name of Japan, 1947 to present)

sake, Japanese rice wine