Qiufen (Autumn Equinox), the 16th solar term on the Chinese lunar calendar, falls on September 23 this year. It marks a time when day and night are nearly equal across China, summer heat fades and cool air creeps in. The ancient Chinese marked this period with three pentads: thunder falls silent, insects retreat into their burrows and water begins to dry up. Du Fu, a famous poet from the Tang Dynasty (618-907), wrote, "At Autumn Equinox the traveler still remains; bamboo dew glimmers faintly in the dusk." It is when river crabs are in the shallows, pink smartweed flowers bloom and autumn is at its loveliest.