What is Irohazaka? A Scenic Mountain Road in Nikko
Irohazaka is a scenic mountain road on National Route 120 that connects the central Nikko area in Tochigi Prefecture with Lake Chuzenji and the Oku-Nikko region.
Irohazaka consists of the First Irohazaka, used for downhill traffic only, and the Second Irohazaka, used for uphill traffic only, with a total of 48 sharp hairpin curves.
Each curve is marked with a sign bearing one of the 48 characters of the traditional Japanese "iroha" syllabary in order, and the road climbs an elevation difference of about 440 meters.
The First Irohazaka stretches about 6.5 kilometers and the Second Irohazaka about 9.5 kilometers, making a combined total length of roughly 16 kilometers.
Selected as one of Japan's 100 Best Roads, Irohazaka is highly regarded as a scenic drive route where the landscape changes dramatically with every turn.
Rather than thinking of it as a simple transit road, viewing Irohazaka as a route that lets you feel the gradual shift of scenery from Nikko to Oku-Nikko makes the journey far more memorable.
Top Things to See on Irohazaka: First vs. Second Slope
First Irohazaka Goes Down, Second Irohazaka Goes Up
The first thing first-time visitors should know is that the two slopes are one-way roads, each with a clearly defined role.
When heading from central Nikko toward Lake Chuzenji and Oku-Nikko, you take the Second Irohazaka (uphill only, 20 curves, lettered "i" through "ne"); on the way back, you take the First Irohazaka (downhill only, 28 curves, lettered "na" through "n").
The road was historically two-way, but constant traffic jams and accidents led to the introduction of one-way traffic, separating uphill and downhill routes.
Knowing this layout makes it easier to plan a route that includes Oku-Nikko on the far side, rather than assuming you will simply turn back.
Combining your visit with attractions such as Kegon Falls, Lake Chuzenji, Senjogahara, and Yudaki Falls in Oku-Nikko turns Irohazaka from a mere passageway into the opening chapter of your trip.
Akechidaira: A Stop for Sweeping Views
Akechidaira, located along the Second Irohazaka, is known as a vantage point where you can look back on Irohazaka itself from a distance.
When accessible, Akechidaira Observatory offers panoramic views of Mt. Nantai, Lake Chuzenji, Kegon Falls, and the First Irohazaka winding below.
The Akechidaira Ropeway, when operating, takes about 3 minutes one way to reach the observatory.
Rather than letting the scenery distract you while driving, pulling over to enjoy the view is both safer and more rewarding for travelers.
The Akechidaira Ropeway is sometimes closed for renewal work, inspections, or bad weather, so check the operating status before your trip if you plan to stop here.
Best Time to Visit Irohazaka
Irohazaka changes its character with the seasons, but it is especially famous nationwide as one of Nikko's top autumn leaves spots.
Known as "the most beautiful place in Nikko for autumn foliage," Irohazaka bursts into vivid color with Japanese maples, mountain ash, and other maple varieties.
Peak foliage timing varies with elevation and weather, but the section from the middle of Irohazaka up to Akechidaira typically peaks in mid- to late October, while the Oku-Nikko side tends to color slightly earlier.
From late April through May you can enjoy fresh greenery, May and June bring azaleas, and summer offers deep mountain greens, giving the road seasonal appeal beyond autumn.
The sense of changing air and scenery as you climb a road with significant elevation gain is a pleasure that can be felt outside of fall, too.
Rather than focusing only on autumn leaves, enjoying the gradual shift in nature from central Nikko to Oku-Nikko is what truly conveys the charm of this road.
How to Handle Autumn Traffic on Irohazaka
Crowded Periods Are Part of the Irohazaka Experience
During autumn foliage season, what is normally a 20-minute uphill drive on Irohazaka often takes 2 to 3 hours due to traffic.
Holiday weekends are even busier, and past records show uphill traffic jams that lasted as long as 6 hours.
Heavy congestion from private cars is common during the autumn leaves season, so visiting on weekdays, during early-morning or late-afternoon off-peak hours, or using public transportation are all good options.
If you do drive during foliage season, be sure to allow plenty of extra time.
Rather than treating Irohazaka as a quick pass-through road, planning your itinerary with congestion in mind, and including time to enjoy Oku-Nikko, leads to a far less stressful trip.
If you must visit at peak foliage time, taking a Tobu Bus (bound for Lake Chuzenji or Yumoto Onsen) from JR Nikko Station or Tobu Nikko Station spares you the stress of driving and waiting for parking.
Check Traffic Information Before You Set Out
Conditions on the day vary greatly with weather and the day of the week.
Dedicated pages provide near real-time information on Irohazaka and surrounding road traffic, congestion forecasts, and live camera feeds.
If you are torn between driving and using public transit, checking the day's conditions first makes planning far easier.
During autumn especially, people and cars tend to converge between 9 a.m. and 3 p.m., and weekend congestion can last into the evening, so checking before heading out is essential.
To avoid the worst of the traffic, consider going up early in the morning on weekends and holidays, or traveling after 3 p.m. on weekdays for relatively smoother passage.
Driving Irohazaka in Winter: What to Watch Out For
Irohazaka is generally open year-round, except during severe weather, heavy snow, accidents, or other road restrictions.
However, snowfall and icy road surfaces are possible from late autumn through early spring, so winter tires (studless) or tire chains are required if driving.
Driving on regular tires may be restricted, so whether traveling in your own car or a rental, always confirm that the vehicle has proper snow equipment.
Nikko City also warns that even on sunny days, shaded sections and bridge surfaces in the Oku-Nikko area above Irohazaka can be icy.
Winter sightseeing here calls for warm clothing, non-slip shoes, proper vehicle equipment, and even attention to fuel levels.
How to Get to Irohazaka: Access and Basic Info
Getting There by Car
Coming from the Tokyo area, take the Tohoku Expressway to Utsunomiya Interchange, switch onto the Nikko-Utsunomiya Road, exit at Kiyotaki Interchange (the terminus), and follow National Route 120 to reach the entrance of Irohazaka.
The drive from central Tokyo normally takes about 2.5 hours, but expect significantly longer travel times during autumn and on weekends.
Getting There by Public Transportation
By train, JR Nikko Station or Tobu Nikko Station serves as the gateway. From the station front, take a Tobu Bus bound for Lake Chuzenji or Yumoto Onsen, which runs via the Second Irohazaka and reaches the shores of Lake Chuzenji in about 45 to 50 minutes.
Discount passes such as the Chuzenji Onsen Free Pass and the Yumoto Onsen Free Pass are available, and choosing one with a wider free zone helps keep costs down if you plan to head all the way to Oku-Nikko.
Toll, Restrooms, and Rest Facilities
Irohazaka was opened toll-free in 1984, and no toll fees are charged today.
Akechidaira, located midway, has restrooms and parking, making it the main rest stop along the Irohazaka section.
On the Oku-Nikko side, you'll find restrooms and rest facilities near the Chuzenji Onsen Bus Terminal on the shores of Lake Chuzenji and around the Nikko Natural Science Museum.
Summary: What to Know Before Driving Irohazaka
Irohazaka is both a route from central Nikko to Lake Chuzenji and Oku-Nikko, and a scenic road with sights worth seeing along the way.
Knowing how to use the First and Second Irohazaka, the views from Akechidaira Observatory, autumn traffic conditions, and winter ice precautions makes everything easier even on a first visit.
Before setting out, check tourism information, live cameras, and traffic forecasts, and build a flexible itinerary suited to the day's conditions.
Treating Irohazaka not just as a route to Oku-Nikko, but as part of an experience where the scenery shifts mile by mile, gives your Nikko trip a far richer dimension.
