Green Carp Fatted Liver

Green Carp Fatted Liver was created at Old Zheng Xing, which was founded in 1862 by Zhu Zhengben and Cai Renxing—whose given names supplied the characters zheng and xing for the original 'Zhengxing Guan.' The 'old' prefix was added later to distinguish the founding restaurant from the many imitators that appeared once the place became famous, making it the acknowledged ancestral house of Shanghai benbang cuisine. According to restaurant tradition, the dish was proposed in the early Republican era by Yang Baobao, son of the owner of Shanghai's Yangqinghe silver-jewelry shop and a habitual customer, who suggested to the kitchen that the livers of black carp—then discarded—might be transformed into a dish. The chefs took livers from wild black carp weighing over five jin, washed them repeatedly, and braised them with bamboo shoots, scallion, ginger, Shaoxing wine, soy sauce, and sugar. By the 1930s the preparation had become Old Zheng Xing's most celebrated cold-weather specialty. 'Sulu' (秃肺) is Shanghai dialect for liver; the name is said to derive from the liver's superficial resemblance to a lobe of lung. Peak season runs from Qingming in early April through the first osmanthus bloom in mid-autumn, when wild black carp are at their fattest. The dish nearly disappeared in the late twentieth century as live-sourcing became logistically difficult; very few Shanghai restaurants now attempt it.

Press gently with the tongue: the liver yields like warm butter—no resistance, only spreading richness—then a deep tide of fish oil and seasoned soy wells up, clean and round, without a trace of fishiness; the bamboo shoot provides a cool, crisp counterpoint that rescues the dish from pure indulgence.

Black carp liver is exceptionally high in fish liver oil—dominated by long-chain polyunsaturated fatty acids including eicosapentaenoic acid and docosahexaenoic acid—which constitutes a large proportion of its mass and accounts for the extraordinary richness. The liver's connective tissue fibres are short and fine; cooking to approximately 65°C denatures surface proteins while the interior remains semi-fluid, analogous to searing foie gras. Any temperature overshoot ruptures fat cells, releases bile compounds—bilirubin and biliverdin—and turns the liver bitter and dry. Removing the dark lateral veins (where bile precursors concentrate) and keeping the gallbladder intact during extraction are therefore critical. The cornstarch slurry finish forms a glossy gel coat that traps surface moisture and moderates further heat transfer into the liver, extending the window of correct doneness.