In summer, many Chinese will resort to dishes that have cooling properties, as dictated by traditional Chinese herbalism. Every Chinese ingredient is deemed either yin or yang, the former associated with coolness and the latter with heat. Then again, it can also depend on the method of cooking, as a yin product can become yang if ingredients like pepper and chillies are added. It’s a minefield of near-mystical theories, but suffice to know that when a dish tastes good, one is left with a feeling of equanimity. This recipe is believed to have cool, yin, properties.