Irohazaka (いろは坂)

Irohazaka is the climb on National Route 120 between Umagaeshi, above central Nikko, and Lake Chuzenji in Tochigi. It is two one way roads: the First Irohazaka, 6,526 m and downhill only, with 28 curves, and the Second Irohazaka, 9,468 m and uphill only, with 20 curves. Each of the 48 curves carries a sign with one letter of the iroha, the old Japanese poem that uses every syllable once, and the road gains about 440 m from bottom to top.

The route began as the path pilgrims took to Mount Nantai, traced back to 782. The First Irohazaka opened in 1954 as Japan's second toll road and the first built by a prefecture, the Second followed in 1965, and both have been free since 1984. The Japan Society of Civil Engineers lists the pair as civil engineering heritage. At the top, Lake Chuzenji formed when an eruption of Mount Nantai blocked the river.

In Initial D, Irohazaka is home to Team Emperor and to Kai Kogashiwa and his father Ken, who live by Lake Chuzenji. The series uses the downhill First Irohazaka, a rhythm of straight, hairpin, straight, and it is where Takumi beats Kai before their rematch at Nagao. Irohazaka arrived in the arcade games with Initial D Arcade Stage Ver. 2.

• The way up is the Second Irohazaka, 20 curves from "i" to "ne", with two rest areas and car parks along it.
• Akechidaira on the way up looks over Kegon Falls, Lake Chuzenji and across to the First Irohazaka.
• At the top the road meets the shore of Lake Chuzenji, the setting for the Kogashiwa family in the series.
• The way down is the First Irohazaka, 28 curves of straight, hairpin, straight. In the series Ken teaches Kai to jump the shortcut at the 33rd corner, the 13th hairpin of the downhill, and the course ends over three bridges across the Daiya River.
• Wild Japanese macaques live along the road.
• The slopes turn red and gold in autumn, with the colour peaking from mid to late October.
• Best way to experience it: in your own car or a hire car, or on one of the guided tours that run on it.

• Each road runs one way only: the Second Irohazaka is uphill only and the First Irohazaka is downhill only, so the loop always goes up the second and down the first.
• The Akechidaira car park charges ¥500 per car. The Akechidaira ropeway is closed for renewal works until 31 August 2027.
• Autumn leaf season and long weekends bring the worst traffic jams of the year on the climb, and the Nikko tourism association warns visitors to allow extra time. Live congestion information is on the Nikko tourism site.
• Feeding the monkeys is banned under a Nikko City ordinance, and they have been known to snatch souvenirs.
• Snow and ice are common on the mountain roads in winter, when winter tyres are needed.
• Racing, drifting and speeding on these roads are illegal. Buses and cyclists share the road.
• Getting there: Kiyotaki IC on the Nikko Utsunomiya Road is the nearest expressway exit. Tobu buses from JR Nikko and Tobu Nikko stations to Chuzenji Onsen run up the Second Irohazaka.

• Last verified: 3 November 2026
• Official link: https://www.nikko-kankou.org/spot/9