KABOSU
Scientific name: Citrus sphaerocarpa
Katakana: カボス
Kanji: 臭橙
Kabosu is a citrus fruit of an evergreen broad-leaf tree in the Rutaceae family. In Japan, its juice is used to improve the taste of many dishes, especially cooked fish, sashimi, and hot pot dishes.
It looks a lot like the Philippine calamansi, but whose scientific name has been given as Citrofortunella microcarpa or Fortunella japonica.