Chicken and duck blood soup was invented by little-known Shanghainese hawker Xu Fuquan, who made the dish by mixing hot chicken and duck blood with the head and feet of a chicken, before boiling it in an iron pot, which he dubbed a "metal cow".
[1] In 1973, during his visit to Shanghai, then-King of Cambodia Norodom Sihanouk tried chicken and duck blood soup and reportedly enjoyed the dish a lot, having consumed countless bowls of it.
[3] Chicken and duck blood soup is described as having a sour-spicy taste.
[5] Chicken and duck blood soup is so famous in Shanghai that one source goes on to label it as a cultural icon of the city.
[7] Kellie Schmitt of CNN describes the dish as one of "Shanghai's weirdest foods", although adding that it "tastes better than it looks".