CREATE TABLE table_2144389_8 (_number INT, japanese_title VARCHAR)

Name the least number for (popup.version)
SELECT MIN(_number) FROM table_2144389_8 WHERE japanese_title = "君のそばで～ヒカリのテーマ～(PopUp.Version)"
SELECT MIN("_number") FROM "table_2144389_8" WHERE "japanese_title" = "君のそばで～ヒカリのテーマ～(PopUp.Version)"