The Irohazaka is the most famous road in Nikko, and one of the best known in Japan. It climbs from the town at about 640 metres to Lake Chuzenji at roughly 1,270 metres, in a series of forty-eight hairpin bends, each marked with a sign bearing one of the characters of the old Japanese alphabet, called iroha, which has forty-eight letters. The road is split into two one-way sections, with the original, built in the 1950s, carrying traffic down and a second, with twenty-eight bends, carrying traffic up, so you never meet oncoming vehicles on the corners.
The hairpins are tight, but the surface is good and the camber is generous, which makes the climb a joy on a bike. Rhythm matters, because the bends come fast, and the gradient requires you to use engine braking on the descent. Wet leaves and fog can make things slippery, and you should watch for monkeys, Japanese macaques, which sit by the road and sometimes wander into the lanes. Do not feed them, because they can be aggressive.
The best time to come is in October and early November, when the maples and birches turn red and gold, and the whole mountainside seems to be on fire. It is also the busiest, and traffic can crawl for hours, with queues stretching back toward town, so start at dawn. In winter, snow and ice often close the road to vehicles without chains, so check before travelling.
At the top, the Kegon Falls drop nearly a hundred metres into a gorge, one of Japan's three great waterfalls, and an elevator takes you down to a viewing platform at its base. There is also a ropeway at Akechidaira, which gives a panoramic view of the hairpins, the lake and the mountains.
Nikko itself has about sixteen thousand people, with fuel and plenty of food.