Nio: The Guardian Kings at Temple Gates

Two towering, muscular figures flank many temple entrances, and one of them always has his mouth open.

Published October 19, 2026 at 12:57 AM JST | By Tokyo Paul

Quick answer: Nio are a pair of fierce guardian statues placed on either side of Buddhist temple gates in Japan. One has an open mouth and the other a closed mouth, representing the sounds a and un, the beginning and end. Often carved in wood and shown in dramatic poses, they protect the sacred grounds and are best admired from a respectful distance.

Who the Nio are

Nio, which means benevolent kings, are guardian figures placed at the entrance of Buddhist temples. They are usually a pair, standing on either side of the main gate, and they are depicted as powerful, muscular beings with fierce expressions. Their role is to protect the temple from harm and to remind visitors that they are entering a sacred space. The gate that houses them is called a Nio-mon. Large temples often have impressive examples, with the statues enclosed in wooden cages or placed in niches on either side of the passage.

Despite their fierce look, they are protective rather than hostile. The sense of strength and watchfulness is meant to guard the grounds and reassure those who enter with good intentions. Some temples place the statues inside small side buildings next to the gate instead of within the passage itself. In either case, you will usually see them as you approach, so the guardians are the first sacred figures that visitors meet.

A pair with open and closed mouths

One of the most recognizable features is the contrast between the two figures. One has his mouth open, as if saying a, and the other has his mouth closed, as if saying un. These are the first and last sounds in the Japanese syllabary and in the Sanskrit alphabet, symbolizing the beginning and the end of all things. The open-mouthed figure is called agyo, and the closed-mouthed figure is called ungyo. Together they express the unity of opposites.

Shrines have a similar pairing in their guardian lion-dogs, called komainu, which also show one open and one closed mouth. Spotting the pair is a pleasant game as you visit temples. Look at the faces, the posture and the muscles, and notice how the two statues balance each other. The same pairing appears in other settings, such as the lion-dog statues in front of shrines and even in the way people describe the first and last sounds in a sentence. Once you learn to notice it, the open and closed mouths show up in many places.

Origins and meaning

The Nio are linked to a Buddhist figure known as Vajrapani, a protector who wields a diamond-like thunderbolt, called a vajra. In Japan, the guardian is shown in a pair and often named Kongo Rikishi, meaning vajra-bearing strongmen. The idea spread along with Buddhism from India through China and Korea. Their muscular bodies and dramatic poses reflect the artistic styles of the time, and they became more elaborate over the centuries.

Many of the best-known statues date from the medieval period, when sculptors created lifelike and energetic figures. The statues are not worshipped in the same way as the temple's main image. They serve as protectors at the threshold, setting the tone for a visit. In stories, the figures are said to have vowed to protect the Buddha's teachings. This idea of a vow gives the statues a quiet nobility, and the intensity of their faces reflects dedication rather than anger.

Famous Nio statues

The Nio at Todai-ji in Nara, standing at the Great South Gate, are among the most celebrated. They date from the early thirteenth century and are attributed to the sculptors Unkei and Kaikei with their assistants. They stand more than eight meters tall and are known for their dynamic poses. At Senso-ji in Tokyo, the Hozomon gate contains a pair of Nio, and giant straw sandals hang on its rear side.

Visitors often photograph the gate and the sandals, which are said to represent the Nio's strong legs and to protect the temple. Other temples across Japan also have notable Nio, from major complexes in Kyoto to small mountain temples. Each pair has its own character, so seeing them is a good reason to explore different regions. Smaller temples in mountain areas often have Nio statues that are less polished but full of character. Weathered wood, local craftsmanship and quiet surroundings give them a distinct charm that rewards the extra travel.

How the statues are made and preserved

Nio statues are typically carved from wood, often cypress, and constructed from multiple pieces joined together. The surface may be painted, though the colors often fade over time. Some figures retain traces of their original pigment, which hints at how colorful they once were. Because they stand at open gates, the statues face weather and wear. Wire mesh or wooden grilles protect them from birds and visitors.

Restoration work is carried out by specialist conservators, who clean, repair and stabilize the wood. Looking closely, you can see details like veins, flowing cloth and flaming hair. The craftsmanship shows the skill of the artists and the importance of the guardian role. Researchers sometimes find inscriptions or documents inside statues during restoration, offering details about the sculptors, the date and the patrons. These discoveries add to the understanding of the temple's history.

Giant sandals and other offerings

At some temples, people offer large straw sandals, called waraji, to the Nio. The idea is that the guardians need strong feet to walk and protect the temple, and devotees pray for healthy legs and safe travels. The sandals are replaced from time to time, often in ceremonies led by local groups. In some places, you may see small offerings or papers left near the statues. These customs vary by temple, and signs usually explain what is acceptable.

Do not leave items unless it is clearly allowed. The sight of an enormous straw sandal hanging beside a gate is a memorable one, and it shows the playful, hands-on side of Japanese religious life. Straw sandals are woven by volunteers using traditional techniques, and the work can take days. Some communities treat the weaving as an annual event, bringing together people of different ages to continue the craft.

Visiting etiquette

At the temple gate, pause for a moment and bow slightly before entering. The custom is a gesture of respect, and many people perform it without thinking. Walk through the side of the gate rather than the exact center, which is traditionally reserved for deities or dignitaries. Photography is usually allowed at gates, but check for signs. Do not climb the barriers or touch the statues. Keep your voice low, and leave space for others to admire the figures.

If the temple has other halls, follow the usual manners: purify your hands at the basin if provided, keep to marked paths and follow instructions on offerings. A calm attitude helps you appreciate the details. Pairing a visit to the gate with a stroll along the approach road is rewarding. Shops often sell regional sweets and souvenirs, and tasting a snack after your temple visit is a pleasant way to complete the outing.

Frequently Asked Questions

Why do Nio have one mouth open and one closed?

The open mouth makes the sound a, and the closed mouth makes un. These are the first and last sounds of the Japanese syllabary, representing the beginning and end of all things. The pair therefore expresses completeness. Open mouth and closed mouth are also described as inhaling and exhaling, so the two figures together are seen as the whole breath of the universe.

Are Nio found at Shinto shrines?

No, they belong to Buddhist temples. Shinto shrines have guardian lion-dogs called komainu, which also come in pairs with one open and one closed mouth. The similarity reflects a shared visual tradition. Lion-dog pairs at shrines show the same open and closed pattern, and spotting the similarity is a nice way to connect temple and shrine art.

Can visitors get close to the statues?

Usually not. Most Nio stand behind protective grilles or in recessed niches. You can see them clearly from the gate area, and the barriers help preserve them for future generations. Staff and fencing keep the statues safe from weather and touch, and visiting at a quiet hour lets you study the faces and muscles without crowds.

Keep Exploring

More guides from Tokyo Paul: Sanjusangendo: A Thousand Kannon Statues in Kyoto, Jizo: Japan's Roadside Guardian Statues and Shimenawa: The Sacred Rope of Shinto.