The idiom "Yī Rì Sān Qiū" (A Day Like Three Autumns) originates from the 'Wang Feng - Cai Ge' chapter of 'The Book of Songs' (Shijing), China's oldest collection of folk songs. The poem expresses deep longing:

'When she gathers kudzu, A day without seeing her feels like three months. When she gathers wormwood, A day without seeing her feels like three autumns. When she gathers mugwort, A day without seeing her feels like three years.'

This is a poem of remembrance, possibly for a woman. Many ancient ballads sang of love, so this poem can be interpreted as a man's lyrics expressing his profound longing for his beloved. The core meaning conveys that even a short period of separation feels incredibly long due to intense yearning.