Major Heat (Dashu), the 12th solar term on the traditional Chinese calendar, falls on July 23 this year, marking the beginning of the hottest, most humid days in China. Ancient Chinese divided Major Heat into three pentads: fireflies emerge from rotten grass; the earth turns damp and sweltering; sudden downpours arrive to offer respite. Yuan Zhen, a poet from the Tang Dynasty (618-907), wrote, "The round moon rises at midnight and fireflies fly in the air." It is when people lean on bamboo l