Black vinegar is an inky black vinegar originating from the city of Zhenjiang in eastern China. The Chinese version uses wheat, rice bran, and glutinous rice. In the mid-1970s, a Japanese brewery began producing black vinegar locally using 100% brown rice and marketed it as a health tonic to be taken by the spoonful. It's since become a popular ingredient; however, it tends to be milder in flavor than Chinese black vinegar.