Li Bai's eighth-century Changgan Xing opens with a wife's memory: her hair barely covered her forehead; she played picking flowers by the gate; her boy came riding a bamboo horse, circling the well, tossing green plums. They lived together in Changgan lane, two children without suspicion. The poem follows her into marriage at fourteen, shyness, then devotion, then his departure down the gorges. Two idioms were cut from the opening lines: qing mei zhu ma for childhood sweethearts, and liang xiao wu cai for innocent young love.
The toy did the work: a bamboo stalk ridden like a horse was universal childhood equipment, so the image compresses an entire era, before marriage, before commerce, before the gorges. The idiom carries the poem's ache inside it: to call someone qing mei zhu ma is to say the love predates the world of transactions, back when the dowry was green plums. It is nostalgia made grammatical.
The claim: the idiom endures because childhood love is the one relationship formed before the self is a vessel, pre-specialization, pre-transaction, and every later love is measured against the well-frame and the toy horse, making the idiom less a compliment than an admission that the mold broke after one use. Verdict: Li Bai's poem supports the wistfulness but not the ranking; his wife loves the man, not the memory. The archive's caution: the green plum is not a standard. It is a souvenir.
Why does the idiom for lifelong love start with a boy pretending to ride?