Beneath the unassuming nickname “Small Stone Bridge” lies an enigma that has taunted historians for centuries. Yongtong Bridge, arching over the Qingshui River outside Zhao County’s west gate, is a masterclass in ancient engineering—and a riddle wrapped in limestone.

Its origins blur across dynasties. Unearthed in 1986, buried inscriptions and stonework hinted at a birthdate: 765 CE, Tang Dynasty. Yet the artifacts’ style—clean, bold reliefs of River Spirits and flying horses—whispers of Sui Dynasty craftsmanship. Could this bridge be a silent sibling of the iconic Anji Bridge (Zhaozhou’s “Great Stone Bridge”), forged by the same visionary minds? The debate lingers, carved into every joint.

Mimicking Anji’s single-arch, open-spandrel design, Yongtong is a scaled-down marvel. Twenty-one precisely aligned limestone ribs span 23.48 meters, their curve so flat—a record-breaking 0.23 ratio—the bridge seems to hover. Four smaller arches perch on the main vault, lightening its load and mirroring Anji’s ingenuity. But while Anji awed with scale, Yongtong seduces with artistry. Its balustrades ripple with 22 square pillars, their surfaces alive with fish darting through stone waves and stallions mid-gallop. Locals quip: “The big bridge showcases merit; the small one, flowers and plants.”

Here, precision meets poetry. Craftsmen left signatures in dragon-scale chisel marks and a scholar’s verse etched into a railing—centuries of hands shaping its identity. The deck, nearly horizontal, still guides travelers as it did Tang officials, its grooves softened by generations of footsteps.

In 1961, Yongtong joined Anji and Fujian’s Anping Bridge as China’s first protected ancient bridges. Not for grandeur, but for whispering secrets of adaptive design: how a 7.26-meter-wide passage could defy eight centuries of floods and quakes, its stones locked without mortar.

Today, lean close. Trace the undeciphered symbols on a weathered pillar. Feel the ridge where a Song-dynasty repair fused with Sui stone. Yongtong endures—a testament to debates unresolved, beauty unyielding, and bridges that straddle not just rivers, but time itself.