雪泥鸿爪 — “Traces of past events or experiences”

This idiom originates from a poem by the Song dynasty literary master and poet Su Shi. His younger brother, Su Zhe (courtesy name Ziyou), once wrote a poem titled "Recalling Mianchi" (渑池怀旧). Su Shi then composed a responding poem, hence its title "Harmonizing Ziyou's Recalling Mianchi.". The poem begins: "What is life like everywhere? It should be like a flying wild goose treading on snowy mud; occasionally leaving footprints on the mud, but the wild goose's path, east or west, is not to be accounted for. The old monk has died and become a new pagoda, the broken wall has no way to show the old inscriptions. Do you remember the rough journey back then? The road was long, people were tired, and the lame donkey brayed."

Mianchi, now Mianchi County in Henan province, is located west of Luoyang and east of Mount Xiao. Su Shi and Su Zhe had once visited Mianchi and stayed in a temple there. The old monk, Fengxian, hospitably entertained them, and they inscribed poems on the temple walls. Later, when Su Shi recalled these scenes through Su Zhe's nostalgic poem, Fengxian had already passed away, and the inscribed walls were likely damaged. Reflecting on his own drifting life, Su Shi was filled with emotion.

In his responding poem, he told Su Zhe: "Life on earth, moving from one place to another, occasionally leaving some traces – what do you think it resembles? I think it's truly like a wild goose flying everywhere, occasionally landing on a patch of snow. The footprints it leaves on this snow are merely accidental, as the wild goose's flight, east or west, has no fixed direction. The old monk Fengxian has passed away, leaving behind only a new pagoda for his ashes. We no longer have the chance to revisit the broken wall where we inscribed our poems. Aren't the old monk's ashes pagoda and our inscribed wall similar to the accidental footprints of a flying goose on the snow? Do you still remember the arduous journey to Mianchi back then? The road was long, we were exhausted, and the donkey brayed from fatigue."

This poem vividly illustrates the transient and accidental nature of human traces and the impermanence of life, giving rise to the idiom "Xuenihongzhao."