The Oi River was one of the great natural barriers along the Tokaido, the vital highway connecting Edo with Kyoto. The Tokugawa shogunate exploited this geography deliberately, forbidding the construction of any bridge or ferry service across the river. The logic was military: an unbridged river was a defensive moat protecting the shogun's capital. But the cost fell on ordinary travelers. During dry conditions, they could hire porters to carry them across the shallows, an entire economy of river-crossing specialists operating from the post towns on either bank. When heavy rains came, particularly during the spring and autumn, the river became impassable. Merchants, pilgrims, and officials found themselves stranded, filling the inns of Shimada-juku and Kanaya-juku while watching the brown water rage past. Some waited a day. Some waited a week.

The Meiji Restoration of 1868 swept away the shogunate and its river-crossing prohibitions. Former samurai loyal to the Tokugawa clan, suddenly without lords or stipends, settled in the Makinohara plateau area south of the Oi River and began cultivating tea. The Makinohara region would become one of Japan's premier tea-growing districts, but first the farmers needed to cross the river reliably. In 1879, the bridge was completed, an engineering answer to a problem that politics had created and nature had amplified. The original structure was entirely wooden, a low-slung walkway supported by wooden pilings driven into the wide, gravelly riverbed. It stretched nearly 900 meters, an extraordinary length for a wooden bridge, reflecting the sheer breadth of the Oi River at this crossing point.

On December 30, 1997, the Guinness Book of World Records certified Horai Bridge as the longest wooden pedestrian bridge in the world at 897.4 meters. But the number itself carries meaning beyond measurement. In Japanese, 897.4 can be read as 'ya-ku-na-shi,' a phrase meaning 'free from misfortune' or 'no trouble.' The wordplay has transformed the bridge into a destination for those seeking good luck, a place where the simple act of walking across becomes an auspicious journey. The bridge is 2.4 meters wide, open to pedestrians and cyclists but closed to motorized vehicles. A small toll of about 100 yen grants access. At the southern foot of the bridge, the Horai Bridge 897.4 Teahouse opened in 2018, serving local Shimada green tea and sweets with views of the wooden span stretching across the river.

The bridge that stands today is not entirely the one built in 1879. In 1965, the wooden pilings that supported the span were replaced with concrete, a concession to durability after floods had repeatedly tested the original supports. But the walking surface remains wood, and crossing Horai Bridge still feels like stepping onto something ancient. The planks flex slightly underfoot. The Oi River spreads wide and shallow below, its gravel bars and braided channels a reminder of the same force that stranded travelers for centuries. On clear days, the view from the bridge includes Mount Fuji to the northeast, its snow-capped cone framing a scene that connects three centuries of Japanese history: the shogunate's strategic prohibition, the Meiji samurai's reinvention as farmers, and the modern bridge that turned a river crossing into a world record.