The Nanhu water caltrop, named after Nanhu Lake in Jiaxing, East China's Zhejiang province, has become a distinctive local delicacy of the city. 

Unlike other water caltrops, the Nanhu variety grows without sharp horns. A folk tale attributes this to Emperor Qianlong of the Qing Dynasty (1644–1911), who ordered the horns removed after being pricked while eating them. Scientifically, the mixed water quality at the confluence of the Yangtze River, Qiantang River, and Taihu Lake causes the caltrop's crown to fall off, preventing horn formation.

The Nanhu water caltrop. [Photo/WeChat account: jxfabu]  

Resembling jade in color and shaped like a traditional Chinese wooden boat, the Nanhu water caltrop has been cultivated for more than 6,000 years in Jiaxing's rivers and lakes. 

The classic preparation is stir-frying, a household dish regarded as a seasonal treat in Jiangnan — the area south of the Yangtze River. Freshly harvested caltrops are selected for their green stems, peeled after a small cut at the base, and then gently stir-fried over low heat. Light seasoning with salt and a splash of water enhances their crisp and tender sweetness, and the dish is finished with scallions for added aroma.  

The Nanhu water caltrops are peeled and placed on a plate. [Photo/WeChat account: jxfabu]  

Though simple, the dish captures the freshness of the summer and the essence of Nanhu Lake, offering a delicate taste that reflects Jiaxing's culinary culture and the gentle charm of Jiangnan.

The stir-fried Nanhu water caltrops. [Photo/WeChat account: jxfabu]