Myogo Honzon (名号本尊)
Rokuji myogo (six-letter myogo)
Namu Amida Butsu (南無阿弥陀仏)
Namu' (南無) means 'becoming a believer,' and the term means 'becoming a believer of Amida Nyorai (Amitabha Tathagata).'
In 'Gebon Gesho' (Lower grade: lower birth) of "the Kanmuryoju-kyo sutra" ('The Sutra of Visualization of the Buddha of Measureless Life,' meaning Amida), it is stated as follows:
With your heart and continuous voice, and concentrating in Junen (10 invocations in Buddhism), call Namu Amida Butsu. Because you are calling the name of Buddha, with those invocations, you will be forgiven the guilt to wander around between life and death for Hachijuokko (an extremely long time).
Since these six letters are the names that Hozo bosatsu (the name of Amida Buddha when he was conducting ascetic practices (Ini, or not yet reaching Satori (enlightenment)) received after conducting ascetic practices and reached Shogaku (true enlightenment), it is also called 'kago.'
Rokuji myogo are thought to be the most esteemed myogo because they show all the power of Nyorai (Tathagata), and they're used as Honzon.
In "Rennyo-shonin Goichidai-ki Kikigaki," a record of the sayings and acts of Rennyo, he said as follows. He said the letters 'Namu' are used only in the teachings of the saint (Shinran). He copied 'Namu Amida Butsu' with mud and hung it in a zashiki (a Japanese-style tatami room), and said that Amida Nyorai praised these Namu Amida Butsu. He said that Namu Amida Butsu should therefore be the fundamental.
As stated above, he said it showed all the power of Amida Buddha.
Kuji myogo (nine-letter myogo)
Namu Fukashigiko Nyorai (南無不可思議光如来)
It is based on a writing in "San Amidabutsu Ge" (Gatha in Praise of Amida Buddha), by Donran, that he saw Amida Nyorai and bowed from the bottom of his heart, showing his belief.
Juji myogo (ten-letter myogo)
Kimyo Jinjippomugeko Nyorai (帰命尽十方無碍光如来)
It is based on a writing in "Muryojukyo Ubadaisha Ganshoge" (Verses on the Aspiration to Be Born in Pure Land) (also known as "Jodoron" (A Treatise on the Pure Land Sutra), "Ojoron" (A Treatise on Reborn)) by Seshin, that he had told Shaka he would devote himself, from bottom of his heart, to Amida Nyorai, so he wished to be in the Pure Land, showing his belief.
Like Kuji myogo, it is displayed at a Buddhist alter as a 'Wakigake' of Honzon. Also, these words (in "Jodoron") are used as ekomon (a verse that transfers merit back to Buddhas, bodhisattvas and past teachers for their further empowerment to bring beings to the way of the Buddha) in Jodo Shinshu.
There is an opinion that the reason Shinran used Myogo Honzon, even though it was popular to worship icons as Honzon at that time, was that Shinran moved very often for propagation without holding temples and living in small thatched huts; thus it was impossible for him to have a wooden statue.
Also, the 'Rokuji myogo,' written by Rennyo on paper or silk to use as Honzon, and given to common people, was 'Myogo Honzon.'
By this, Honzon began to be enshrined in each house, and the teaching spread rapidly.
In Buddhist sects that practice the conception of Buddha, or 'Kanso Nenbutsu,' Buddhist statues are considered important, but in Jodo Shinshu the conception of Buddha isn't practiced. Following giving commentary in "Kanmuryoju-kyosho" (also known as Kangyosho) (Commentary on the Meditation Sutra) by Shandao, and "Senchaku Hongan Nenbutsu-shu" (also known as Senchaku-shu) (Passages on the Selection of the Nenbutsu in the Original Vow) by Honen, Shinran stated in 'Gyo no maki' (a theme of Practice) of "Ken Jodo Shinjitsu Kyogyosho Monrui" (also known as "Kyogyoshinsho") (Selected passages revealing the true teaching, practice and attainment of the Pure Land) that the righteous practice is to call the name of Buddha, regarding the calling of 'Namu Amida Butsu' as the most righteous and important practice (Shojo no gyo) next to wishes by Amida Buddha.
Because doctrine decides 'Dokuju' (chanting sutras), 'Kanzatsu' (meditation), 'Raihai' (reverence) and 'Sandan Kuyo' (holding ceremonies) as Jogyo (sub-practices), there is no necessity for them to be limited to statues and pictures, so the use of Myogo Honzon does match the doctrine.
However, certain sects of Jodo Shinshu do not relate Myogo Honzon to regarding 'Myogo only' as Honzon. This is because there is no condition for being a subject of salvation by Amida Buddha. It is not a real wish of Amida Buddha for blind people and people who cannot read kanji (Chinese characters) (like foreigners) to be excluded from the subject of salvation. Also, people who cannot speak cannot conduct 'Shomyo' (Invocation of the Buddha's Name), but they can conduct jogyo, thanking Buddha and his virtue. No matter whether it is a wooden statue, a picture or myogo, as a hoben (expediency) for the power of Amida Nyorai, which has no color or shape, Honzon is enshrined and being prayed in appreciation of Amida Nyorai's virtue.
In "Rennyo-shonin Goichidai-ki Kikigaki," it is said as follows. Rennyo Shonin says. It is inappropriate to say hoben as a bad behavior. By using hoben, Hairyu no gi (comparing two things, abolishing one and allowing the other to flourish), which enlightens the truth, must be known very well. Through the Zengyo Hoben (the way to lead people skillfully) by Amida, Shaka and high priests, the true belief will be granted. The meaning of hoben is stated as above.
However, the book states as follows. In other sects, it is said that a picture is better than myogo and a statue is better than a picture. In this sect, a picture is better than a statue and myogo is better than a picture.
As stated above, there is a tendency to think 'calling myogo is the best thing to do.'
However, the essence of this sentence is to emphasize devotion to Amida Buddha's power, not to worship Amida Buddha as a statue. Considering the historical background, rich people such as nobility constructed temples, donated statues and pictures, and prayed. However, Rennyo gave out myogo, which can be handed to everyone. It was to teach everyone that common people could also receive salvation through Amida Buddha by praying to myogo, which could be handed to anyone, without any difference between the rich and the poor.
Therefore, if the power of Amida Buddha is known and receives devotion, the shape of Honzon, whether it is a wooden statue, a picture or myogo, does not matter.