Irohazaka: The Slope That Speaks in Letters
Somewhere north of Tokyo, past the cedar avenues and the shrine gates of Nikko, the road stops being a road and becomes a sentence. It climbs out of the valley in switches, each corner marked with a wooden sign carrying a single character, and the characters come in order, one after another, the way they were arranged a thousand years ago in a poem that uses every sound in the old Japanese syllabary exactly once. You climb the mountain by reading it. By the time you reach the top you have spelled out the whole alphabet of a dead language in asphalt.
The road is called Irohazaka, and the name is literal. Iroha is the poem. Zaka means slope. Together they describe two narrow one-way mountain roads that together carry forty-eight hairpins, one for each character of the iroha, stacked up the flank of Mount Nantai between the old town of Nikko and the shore of Lake Chuzenji. It is about fifteen minutes of driving that has been fascinating people for centuries, first as a pilgrimage route for mountain ascetics, later as a toll road for a growing nation, and now as a quiet public highway with an outsized claim on Japanese car culture.
This is not a record-setting road. It is not the highest, the longest, or the fastest. It is something rarer: a piece of road engineering that carries its own history in its signage, and a place where a certain kind of driver has been coming to test their nerve since long before anyone thought to film it. This is the second stop in our Japan Drives series. The first was Hakone, the caldera rim above Lake Ashi where Japan’s manufacturers bring their prototypes and the roads flow rather than switch. If Hakone is Japan’s test track, Irohazaka is its examination hall.
A Road Older Than the Cars That Love It
The first thing to understand about Irohazaka is that it did not exist for cars. It existed for people walking toward a sacred mountain. Mount Nantai, the volcano that rises above Lake Chuzenji, was opened to mountain worship in 782, and for a thousand years after that, ascetics made their way up this slope on foot toward the summit and the temple at the lake. The foot of the climb is still called Umagaeshi, which translates to “turn the horse back,” because horses were forbidden on the sacred mountain, and for centuries women were barred as well. The women’s worship hall, Nyonindo, still stands partway down the First Irohazaka, a reminder of how old the traffic on this slope really is.
The road as a road is newer. A Taisho-era route replaced the walking track in the early twentieth century, rickshaws used it from around 1902, an electric tram reached Umagaeshi in 1913, and buses began running in 1925. The surface stayed gravel and only three to four meters wide until a rebuild in the early 1950s. On October 1, 1954, the modern road opened as the Nikko Road, only the second toll road in Japan. Eleven years later, on October 7, 1965, a second, wider road was opened alongside it, and the two halves of the mountain got their split personality: one road climbing, one road descending, each one-way, together adding up to the forty-eight hairpins that give the slope its name.
The count has a history of its own. The pre-war road was said to have forty-eight hairpins. The 1954 rebuild trimmed that to thirty, and when the second road opened in 1965 with twenty curves of its own, the older road was cut by two so that the pair would total forty-eight once more. It is the kind of tidiness that only makes sense in Japan: a road that insists on spelling the entire syllabary, even when the engineering would rather not. In recognition, Irohazaka was named to Japan’s 100 Best Roads in 1986 and folded into the Japan Romantic Road the following year. It has been free of tolls since October 1, 1984, and it remains a plain working highway, used every day by buses, locals, delivery vans, and tourists who came for the leaves and found the corners instead.
The Climb: Twenty Letters Up
You climb the Second Irohazaka, and it is the one that carries the traffic up. It runs about nine and a half kilometers from Nikko to the lake with twenty hairpins, and if you are paying attention you will notice that it is unapologetically a race between you and the gradient. The signs start at the top of the alphabet and work forward: the first corner you meet is marked, and the sequence runs in order as you gain altitude, each character announcing itself just as you finish braking from the last one. Cars climb only. In 2019, the upper stretch of the Second road, from the Akechidaira parking area up toward the lake, was made fully one-way toward Chuzenji, which means you can no longer drive from the lake straight back down to the viewpoint. You descend the other road and climb this one again, and honestly, that is a feature.
The numbers are modest on paper. The switchbacks gain roughly 440 meters of elevation to reach a lake that sits at 1,269 meters, which works out to an average grade in the single digits and a maximum that the road has never bothered to advertise. This is not a pass that punishes you with a wall of gradient. It punishes you with density. The corners come close together, short straights between them, the road pinching to near single-lane width in places on the descent, and the upper end flanked by forest that goes gold and copper in late October. There is very little room for a mistake and almost no room for a big car to breathe.
That is what gives the climb its character. A powerful car cannot simply overwhelm Irohazaka; it has to be placed, corner after corner, with the patience of someone writing out a sentence by hand. Traction out of the slow uphill bends matters more than top speed ever will, and it is probably why this slope became, in the imagination of a generation, Mitsubishi Evolution country. More on that in a moment.
The Descent: Twenty-Eight Letters Down
Going down, you are on the First Irohazaka, the older road, now one-way for descending traffic only. It runs about six and a half kilometers with twenty-eight hairpins, several of them so tight that the signboards have to be read at walking pace. It is narrower and steeper-feeling than the uphill road, a continuous negotiation between gravity, brakes, and the small voice telling you that the guardrail is not as tall as you would like. This is where Nyonindo sits, the old women’s worship hall, a single wooden building pressed against the hillside, and this is where the road most clearly still belongs to the mountain. The corners are not numbered here either. They are lettered, na through n, the back half of the syllabary, so that the descent finishes the sentence the climb began.
The Summit Moment
You arrive at the lake, and the road exhales. Lake Chuzenji is a caldera lake, formed when Mount Nantai erupted and its lava dammed the valley about twenty thousand years ago, and at 1,269 meters it has a fair claim to being the highest natural lake in Japan. The village of Chuzenji Onsen sits at its edge, with lakeside villas that date back to when this was summer escape territory for diplomats and writers. After the tight, enclosed climb, the sudden openness of the water is the whole payoff, and the color in late autumn, when the shoreline maples turn, is the reason the road jams every weekend in foliage season.
The classic view, though, is one you reach on the way up rather than at the top. Roughly mid-climb, the Akechidaira parking area opens onto a panorama that takes in both Kegon Falls and the lake at once, with Nantai looming over the water. Normally a ropeway lifts visitors the last stretch to the observatory, but it has been out of service since January 16, 2026, for a full renewal, with reopening planned for late 2027. The parking area stays open, and the view from it is the one worth the stop, cable car or not. Below the road surface, if you climb down to the base of Kegon Falls, you get the other half of the picture: a ninety-seven meter drop where the lake’s outflow, the Daiya River, throws itself off the plateau and disappears into the gorge.
The Car: Why an Evolution Belongs Here
Full disclosure, the same way we gave it at Hakone: no factory ever staged an official test at Irohazaka, and no manufacturer brochure names this slope. The car that belongs here comes from fiction, and the fiction is precise enough that it has shaped how a whole generation sees the road. In the manga and anime Initial D, Irohazaka is the home course of Team Emperor, a Tochigi crew that races nothing but Mitsubishi Lancer Evolutions and calls itself the king of the mountains. Their leader, Kyoichi Sudo, drives a black Lancer Evolution III, chassis code CE9A, and the series is explicit about why this road suits him: racing on a one-way mountain pass demands the discipline of a circuit, not the improvisation of a street racer.
It is fan canon, not a factory endorsement, and we are framing it that way. But the pairing makes real mechanical sense. A short, tight, uphill hairpin road rewards exactly what the Evolution line was built for: all-wheel drive clawing out of slow corners, a torquey turbocharged engine that pulls from low revs, and brakes that can survive being asked again and again. The Evolution started life in 1992 as a homologation special for the World Rally Championship, a two-liter turbo four with the now legendary 4G63 engine, and the third generation, the CE9A of 1995, is the one that made the name in the mountains as well as on gravel. Its rally pedigree is not fiction: Tommi Makinen won the World Rally Championship drivers’ title four years running, 1996 through 1999, at the wheel of Evolutions. Active Yaw Control arrived with the Evolution IV in 1996, and by then the car’s reputation as the all-weather mountain weapon was already set.
The car in these photographs is that third generation, in the black it wore in the story. It is a boxy, honest four-door with a vented bonnet, a deep front bumper carrying two big driving lamps, flared arches, and a tall rear wing, and it looks exactly like what it is: a homologation special that happened to have four doors and a boot. On a road where the corners come every hundred meters and the straights barely exist, it is the right tool for the job in a way that a bigger, heavier, more powerful car never quite manages. Irohazaka does not care how fast you are. It cares how well you can read.
After the Climb: Waterfalls, Monkeys, and a Hot Bath
The mountain does not end at the lake. Beyond it, the plateau opens into Senjogahara, a marshland of boardwalks and birch trees that is one of the great walking landscapes of the region, and past that the hot spring town of Yumoto closes the loop. Below the lake, the World Heritage core of Nikko waits, the shrines and temples of Toshogu, Futarasan, and Rinnoji, gilded and cedar-shaded and older than any road on this mountain. And all along the Irohazaka road itself, if you keep an eye on the verge, you will meet the mountain’s other residents: wild Japanese macaques, bold enough that Nikko City once passed Japan’s first no-feeding ordinance after they began raiding tourists for food.
Then, when the driving is done, there is the oldest part of the Nikko bargain. This is onsen country, and the bathhouses around Chuzenji and down in the valley have been putting tired travelers back together for centuries, long before the first toll gate went up in 1954. Soak, eat something warm, and watch the light leave the lake, and the slope you just read from top to bottom will start to feel less like a road and more like a place you will want to come back to.
Irohazaka · Tochigi, Japan · Open in Google Maps
Go Before the Colors Peak
The practical part. Irohazaka is open all year, with snow clearing in winter, but winter tires are required and the road closes temporarily in heavy snow, so check conditions before you commit in the cold months. The one-way layout is fixed: the Second Irohazaka climbs, the First descends, and remember that the upper Second, from Akechidaira up to the lake, runs one-way toward Chuzenji, so plan your lookouts on the way up rather than expecting to come back down to them. The Akechidaira Ropeway is closed for renewal until late 2027, though the parking area and its panorama remain open.
Timing is everything here. Autumn color runs from mid-October into early November, peaking around late October, and it arrives at the top of the hill before it reaches the bottom. Peak weekends are genuinely congested: a climb that normally takes twenty minutes can stretch into hours when the leaves are at their best, so go on a weekday, early, and give yourself the road rather than the queue. The rest of the year the slope is quiet and quick, and the drive is short enough that you can loop it more than once in an afternoon, up the Second and down the First, reading the alphabet in both directions.
Bring a car with a good gearbox, good brakes, and a short wheelbase, and bring patience for the parts where the road narrows and the bus ahead of you is taking its time. Irohazaka has been climbed on foot, on horseback, by rickshaw, by tram, and now by everything with four wheels. It has outlasted the language that named it and the empire that charged for it. Forty-eight corners, one for each letter, and every one of them still waiting to be read.
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