In Chinese, an idiom "杯弓蛇影" is related to Summer Solstice.

According to the records of Fengsutong (a book about Chinese customs), written by Ying Shao from the Eastern Han Dynasty (AD25-220), a man named Du Xuan attended a banquet on Summer Solstice, where he mistook the shadow of a bow in his cup for a snake and he had to drink it out of fear.

After the banquet, he felt chest pains and a bellyache and couldn't recover even after seeing many doctors. Finally, he found he had mistaken the shadow of a red crossbow on the wall for a snake in his cup and recovered. Later, people used this idiom to refer to people who are suspicious and frighten themselves.