The torch-lighting ceremony for the 2025 Asian Winter Games was held at Sun Island Scenic Area in Harbin

That winter was especially harsh. Ice sealed the mountains, wood was damp, and even flint was nowhere to be found. 

A boy went to the river to chisel ice and catch fish. By chance, he lifted a piece of ice—thick in the middle, thin at the edges—and held it toward the sun. Suddenly, his face tingled with heat. He caught no fish and returned home, recounting the odd experience to his grandfather. 

The old man's eyes lit up. He pulled the boy back to the river. The ice was still there. He told the boy to hold it toward the sun again, then took a small pinch of dried moxa from his sleeve and placed it beneath the ice. 

Sunlight passed through the clear ice and gathered into a bright, focused point of light, settling steadily on the moxa.

A wisp of blue smoke rose quietly. There were no sparks, no crack of flint—fire seemed to awaken slowly from a long sleep. The center of the moxa glowed dark red, spreading with calm persistence. The grandfather handed over slightly damp twigs. First came a trace of steam, then a red glow seeped through the wood—it truly caught fire.

The boy jumped up in excitement. Tugging at his grandfather, he asked, "Why can ice start a fire?"

The old man traced a slow circle in the boy's palm with his finger. "Look at that piece of ice. Thick in the middle, thin at the edges. Like a bronze mirror, it gathers light from all sides into one point. The heat at that point is fiercer than the summer sun."

"Then why must we use moxa?"

"Mugwort leaves, dried and rubbed into fluff, are soft and full of tiny pores. Air hides inside and cannot escape." The old man lifted the half-burned moxa in his palm. "It catches fire easily, but does not flare up. It smolders, slowly storing heat. Damp wood cannot take a fierce flame—it needs this gentle, patient kindling."

He paused and looked into the grey distance. "The sun is the fire of heaven. Ice comes from the water of earth. Mugwort grows between heaven and earth. In its veins are the memory of sunlight and the spirit of rain. It is born to guide the meeting of heaven's light and earth's breath."

That winter, the boy's family never suffered from the cold again.

Many years later, the boy became an old man. He told the same story to another boy.

And so, for three thousand years, it has been passed down.

Ice lens made by the team from the School of Mechanical and Electrical Engineering, Harbin Engineering University

后记

From a boy in the Warring States era lifting a piece of ice by chance, to the 37-kilogram "super ice lens" on the stage of the Harbin Asian Winter Games, three millennia are pierced by the same beam of sunlight. The ancients observed the heavens and understood the nature of things, using ice and moxa to draw down celestial fire. Today, that wisdom is inherited and renewed, allowing the flame of civilization to cross time—still burning bright.