Yan fan blue

Quick answer：

Yan fan blue is a traditional Chinese description for a particular facial feature and color combination. 'Yan' refers to a prominent chin, often associated with a heroic or distinguished appearance in Chinese culture. 'Blue' could be a metaphorical or literal description of the skin tone or coloration around the chin. In the context of fashion or beauty, it might describe a particular style or makeup technique. There is no specific, widely recognized definition of 'yan fan blue' in a scientific or technical sense.