Nio Pair, Agyo and Ungyo.
The Nio (Benevolent Kings) are a pair of protectors who stand guard outside the temple gate at most Japanese Buddhist temples, one on either side of the entrance. In Japan, the gate itself is often called the Nio-mon (literally Nio Gate). Their fierce and threatening appearance wards off evil spirits and keeps the temple ground free of demons and thieves. In the earliest accounts from India, the Nio were said to have followed and protected the Historical Buddha when he traveled throughout India. The Nio were later adopted by other Asian nations and Japan into the Buddhist pantheon.
In Japan, each is named after a particular cosmic sound. The openmouthed figure is called “Agyo,” who is uttering the sound “ah,” meaning birth. His closed-mouth partner is called “Ungyo,” who sounds “un” or “om,” meaning death. Other explanations for the open/closed mouth include: (1) mouth open to scare off demons, closed to shelter/keep in the good spirits; (2) “Ah” is the first sound in the Japanese alphabet, while “N” (pronounced “un”) is the last, so the combination symbolically represents all possible outcomes (from alpha to omega) in the cosmic dance of existence. The first letter in Sanskrit is “Ah” as well, but the last is “Ha.” Nonetheless, the first and last sounds produced by the mouth are “Ah” (mouth open) and “M” (mouth closed). The Japanese “n” and the Sanskrit “m” sound exactly the same when hummed with mouth closed. The spiritual Sanskrit term AHAM thus encapsulates the first letter-sound “A,” the last letter-sound “HA,” and the final sound “M” when the mouth is closed.
At some Buddhist temples, the Nio guardians are replaced with a pair of mythical and magical Shishi Lion-Dogs — one with mouth open, the other closed.
Surprise is often the reaction the first time you see Nio, the guardian statues at many of the larger Buddhist temples in Japan. With their bare-chested bodies rippling with muscles, fierce visages, and brandishing weapons they seem violent and threatening, quite antithetical to concepts most people associate with the Buddhist religion: compassion, peace, serenity, non-violence etc.
The Nio are there to guard and protect the temple from evil spirits and demons but also human robbers. The vast majority of Nio are made out of wood and are usually housed in their own gate houses to protect them from the weather.
These Niomon, Nio gates, are often the first gate leading to a temple. In Kyushu, especially in the Oita area, the tradition is to carve Nio out of stone and these will often be found outside exposed to the elements. There is also a modern stone Nio design that is appearing more and more throughout the country.
Like other forms of Buddhist art in Japan there are a wide range of styles for Nio. Some were created by highly ranked artists and have been repaired and renovated and sometimes freshly painted. Others have virtually no paint left except for traces, and yet others display layers of peeling that show earlier renovations.
Some Nio are quite crude but quite expressive, made by folk artisans, but no matter their pedigree or age, Nio always come in pairs, and, like the komainu, one will have an open mouth, the other closed.
The open-mouthed one is making the “a” sound and is known as “agyo” and the closed-mouth is making the “n” sound and is called “ungyo“. These are the first and last syllables in Japanese and symbolize beginning and end, birth and death, equivalent to the alpha and omega in Greco-European culture.
The word nio itself is said to mean “Benevolent Kings” and some stories say they traveled with and protected the historical Buddha. Nio are also known as Kongo Rikishi and Shukongoshin.
Alternatively nio are known as Misshaku Kongo and Naraen Kongo. Like their Chinese and Korean counterparts they are believed to be Hindu deities, Vajra Dahra, thunderbolt holders, incorporated into Buddhism as protectors, however there is a theory that suggests that the Greek god Heracles (Hercules) had some influence over their form with the spread of Greek culture from the first to sixth centuries CE in the Buddhist lands of Gandhara, in what is today modern-day Afghanistan and Pakistan.
The oldest extant examples known in Japan are from Horyu-ji Temple in Nara and are dated 711. Probably the most famous one are the pair found at Todai-ji Temple in Nara, towering 26 ft in height, they date from 1203. The nio at Shitennoji Temple in the Tennoji district of south Osaka are also well noted as are the nio guardians at Ninnanji Temple in Kyoto.
Read more: http://www.japanvisitor.com/japanese-culture/nio-guardians#ixzz4Kk3mLI2y