Chicken and Duck Blood Soup

Around 1925, a street vendor named Xu Fuquan set up a stall outside Shanghai's City God Temple using a split cast-iron pot known locally as 'Iron Ox': one half blanched fresh blood over a small coal fire; the other simmered a long broth from chicken heads and feet. Customers watched him ladle assorted offal—heart, liver, gizzard, intestines—into each bowl, add soft blood cubes, and finish with a scatter of scallion and a thread of chicken fat. The soup was counted among Shanghai's 'four great street bowls,' alongside noodle-gluten soup, soy-puff vermicelli soup, and curry beef soup, all of which were prized by longtime residents. Its fame ascended to national legend in 1973, when Cambodian Prince Norodom Sihanouk, living in Chinese exile, visited Shanghai: chefs travelled to Nanxiang to slaughter 108 local grass-fed chickens in order to collect unlaid eggs (鸡卵) of uniform diameter, color, and shape—the prince drank two full bowls and the story entered city lore.

The broth arrives piping hot and clear gold; the first sip is clean and savoury, chicken fat rounding the finish. Blood squares glide off the spoon without resistance, barely set and trembling. Gizzard gives a firm, pleasant chew; liver dissolves almost at a touch. The whole bowl warms every corner of the body.

Blood proteins—chiefly hemoglobin and serum albumin—begin to denature and coagulate between 60 and 70°C, forming a tender gel; overcooking drives further aggregation, causing the block to shrink, open with holes, and turn grainy. Chicken liver contains short, fine collagen fibres that set rapidly—removing it from heat the moment it changes colour preserves a barely-set, custard-like centre. Broth savouriness comes from the synergistic interaction between free glutamate (released from bone and connective tissue during long simmering) and inosinate nucleotides (from muscle tissue), multiplying perceived umami severalfold. Chicken fat carries fat-soluble volatile aromatics and gives the soup its characteristic oily sheen and round finish.