The yuzu is a citrus fruit originating in East Asia. Believed to be a hybrid of sour mandarin oranges and Ichang papeda (a primitive citrus), the fruit resembles a small grapefruit. Its uneven skin can be either yellow or green depending on the degree of ripeness. Although first grown in China, it was introduced to Japan and Korea during the Tang Dynasty, where it is most widely cultivated today. The yuzu has an enchanting fragrance that boosts the flavor of juices, sauces, and other toppings with its zest. Frequently used at high-end restaurants, one cut into the yuzu releases an intoxicating aroma of lime, lemon and grapefruit combined.