Published October 20, 2026 at 8:20 PM JST

At Owari Okunitama Shrine in Inazawa, thousands of men in white loincloths gather each late winter to carry prayer bamboo and ask the gods to clear away misfortune.

Quick answer: The Konomiya Hadaka Matsuri, formally the Naoi Shinji, is a winter purification ritual held at Owari Okunitama Shrine (Konomiya) in Inazawa, Aichi Prefecture. It is usually held in February or March, on the 13th day of the first month of the old lunar calendar, and organizers set the exact day each year. Thousands of men in loincloths carry prayer bamboo into the shrine while a chosen figure called the shin-otoko receives the crowd's wishes for good luck.

A midwinter ritual at Owari's provincial shrine

Owari Okunitama Shrine stands in Inazawa, Aichi Prefecture, a short rail ride from Nagoya. Locals call it Konomiya, and the festival that takes place there each year is known as the Konomiya Hadaka Matsuri, or Naked Man Festival. Despite the English nickname, it is first and foremost a Shinto purification rite, and the formal name is the Naoi Shinji, a ritual to drive away misfortune.

Dates follow the old calendar. According to Aichi Prefecture's tourism site and the Japan National Tourism Organization, the festival is held on the 13th day of the first lunar month, which means it falls in February or March by the modern calendar. In 2026 that day was Sunday, March 1, and the main rite began in the afternoon.

The shrine itself has deep roots in the region. Aichi Now explains that during the Nara period the shrine stood beside the provincial government office, which is why it was designated the sosha, or gathering shrine, of Owari Province. Because the provincial governor performed its rites in person, it came to be called Konomiya.

The main hall, worship hall and gate are described by the prefecture as Important Cultural Properties, and five large natural stones stand in a circle behind the main hall, suggesting an ancient place of worship. For visitors, the shrine grounds are a calm backdrop even outside festival season.

Origins in the Nara period and the Edo-period tradition

The festival is old. Two Japanese travel guides date its beginning to the year 767, while the prefecture and national tourism sources simply say it goes back roughly 1,250 years. According to Aichi Now, the Naoi Shinji began when the provincial governor of Owari held a purification ritual at the shrine to pray for protection from misfortune and illness.

The local winter custom of pilgrimage in a minimum of clothing was combined with this ritual in the late Edo period, which is how the festival acquired the form seen today.

One of the lasting ideas behind the rite is that bad luck can be passed to another. In this rite, a central figure takes on the community's misfortune on everyone's behalf. That idea of shared renewal remains the heart of the festival today.

Travel writers often list the Konomiya festival among Japan's best-known hadaka matsuri, alongside the Saidaiji Eyo of Okayama. One Japanese guide also counts it among three well-known unusual festivals of the Owari area, together with Atsuta Shrine's Busha Shinji and the Kinekosa Matsuri.

The shin-otoko and the naoi bamboo

Two elements stand at the center of the day. The first is the shin-otoko, or god man, also called the naoi-nin. Japanese sources describe him as a figure chosen through prayer and a lottery, and the JNTO notes that he spends several days in seclusion and prayer beforehand. According to the festival tradition, touching him is believed to transfer one's bad luck, which draws the crowd toward him.

The second is the naoi-zasa, bamboo grass decorated with cloths on which worshippers have written their prayers. Teams of men carry these bundles into the shrine as stand-ins for the worshippers, offering them so that misfortune is absorbed and left behind at the shrine.

Once the shin-otoko has taken on the community's troubles, the crowd's rush ends and he is guided into the shrine's ritual hall. A later night ceremony, which a Japanese family guide says begins at around three in the morning, sees the shin-otoko carry a clay ball said to hold the misfortunes, which is discarded and buried by a priest to pray for peace.

Another Japanese guide notes that since 2024 women have been able to take part in the bamboo offering ritual, a sign of how the tradition continues to evolve. As always, check the shrine's current announcements for who may join and how.

What participants wear and who takes part

Participants dress in a simple white sarashi loincloth and white tabi socks. The Aichi prefectural guide explains that men aged 42 and 25, ages considered unlucky in Japanese tradition, are the central participants, and men from throughout the Owari region gather to join them. The JNTO page mentions a figure of about 9,000, although such numbers vary by source and year.

Teams from local neighborhoods and organizations form groups, carrying the naoi bamboo and encouraging each other with shouts. Sake is sometimes shared for warmth, and some participants are doused with buckets of cold water as part of the purification, according to the JNTO.

Spectators play a role as well. Thousands of onlookers line the shrine approach and cheer, creating an energetic, communal atmosphere. The event is traditional, and visitors are asked to treat it with the respect due to a religious ceremony.

Families sometimes wonder whether it suits children. Because the crowd is dense, the main scrum is intense and the schedule can run late, a family guide recommends keeping a safe distance, avoiding late-night viewing with young children and following the organizers' instructions at all times.

How the day unfolds

Exact times vary, but a Japanese guide to the 2026 festival outlines the pattern. Early in the morning, visitors can receive purification prayers and a protective charm. The guide suggests arriving around noon to secure a viewing spot along the approach.

At about 15:00 the shin-otoko attends the main ritual in the hall, and at around 16:00 groups of men run into the shrine offering their bamboo grass. This is the moment when the dense scrum begins, with crowds surging toward the shin-otoko.

There is also a sweet and sustaining element. Each year, nearby districts offer a giant rice cake, described by Aichi Now as weighing about four tonnes. It is cut and shared with visitors after the festival, and eating a piece is believed to bring good health.

Because the festival is held on a lunar date, the schedule is announced by the shrine each year, and details such as timing or event structure can be adjusted. The shrine's contact line and the official festival information are the best places to confirm the latest plan.

Viewing safely and getting there

Inazawa is easy to reach by rail. According to Aichi Now, the shrine is about a three-minute walk from the north exit of Meitetsu Konomiya Station, which can be reached on the Meitetsu line from Nagoya. Alternatively, you can ride the JR Tokaido Line to Inazawa Station and walk about 15 minutes.

Traffic is restricted around the shrine for three days before and after the festival, and the shrine's own parking is unavailable, so public transport is strongly advised. Meitetsu typically adds extra train cars on busy days, according to a Japanese guide.

Late winter in central Japan is cold, so dress warmly. A family guide suggests a thick coat, scarf, gloves, ear covers and hand warmers, and recommends a baby carrier rather than a stroller in crowds and a raincoat rather than an umbrella, which takes up space.

Stay behind barriers, follow staff directions, keep your distance from the central scrum, and avoid sudden movements in the crowd. If you want a calmer experience, visit the shrine on a quiet day to see the grounds, then return to the area for the festival atmosphere.

Local color and what to see nearby

The giant rice cake is one of the most charming parts of the festival. Nearby districts offer it each year, and distribution of the cake the day after the main rite is a gentle counterpart to the energetic scrum before.

The shrine grounds are worth exploring at leisure. Aichi Now describes admission as free, with a visiting window typically from morning to late afternoon, and it notes that the shrine offers amenities such as toilets and wheelchair loans, although stairs lack an elevator or ramp.

Keep in mind that this is a living religious tradition rather than a performance. Photography is common, but be mindful of participants' dignity and follow any shrine signs. A quiet bow at the shrine is a lovely way to end a visit.

Nagoya is the nearest big city and offers plenty of dining and sights, so it makes a convenient base for a day trip to Inazawa. Whether you attend in person or simply learn about the tradition, Konomiya stands as a vivid example of Japan's community-centered winter rites.

Frequently Asked Questions

When is the Konomiya Hadaka Matsuri held?

It is usually held in February or March on the 13th day of the first lunar month. In 2026 it was on March 1. The shrine and local organizers set the exact date and schedule each year, so check the official information before you plan your trip.

Who can take part in the festival?

Men aged 42 and 25, considered unlucky ages, are the main participants, joined by thousands of others from the Owari region, according to Aichi Prefecture. Participants wear white loincloths and tabi socks. One Japanese guide says women have been able to join the bamboo offering since 2024, so ask the shrine for current rules.

Is the festival suitable for visitors with children?

Many families watch from the shrine approach, but the crowd is dense and the main rite is intense. A family-oriented guide recommends staying at a safe distance, skipping the late-night ceremony with young children, dressing warmly, and following staff instructions throughout.

Further reading: the Japan National Tourism Organization page on the Konomiya Naked Man Festival, the Aichi Now event page for the Konomiya Hadaka Matsuri and the Aichi Now page for Owari Okunitama Shrine.

Keep exploring: Nagoya Festival: Three Heroes, Nine Floats and a Golden Autumn Weekend; Saidaiji Eyo: A Winter Night of Lanterns, Drums and Sacred Sticks; Hamamatsu Matsuri: Kites Over the Dunes, Lantern-Lit Floats by Night; Kishiwada Danjiri: Racing Floats and Perfect Corners in Osaka.