TL;DR: Nhật Quang Bodhisattva (also called Nhật Diệu, Nhật Quang Biến Chiếu) and Nguyệt Quang Bodhisattva (also called Nguyệt Tịnh, Nguyệt Quang Biến Chiếu) are two Bodhisattvas attending on either side of Medicine Buddha Lưu Ly Quang, representing the light of the Sun and Moon shining everywhere without darkness. In the Medicine Buddha Sutra, they are regarded as the foremost among countless Bodhisattvas of the Tịnh Lưu Ly realm, will successively take the Buddha's place, and are key assistants in the Medicine Buddha practice. In Esoteric Buddhism, they also appear on the Thai Tạng Giới and Kim Cương Giới Mandalas with their own forms, secret names, and samaya symbols.
Who Are Nhật Quang Bodhisattva and Nguyệt Quang Bodhisattva?
Nhật Quang Bodhisattva (日光菩薩, Sanskrit: Sùrya-prabha) and Nguyệt Quang Bodhisattva (月光菩薩, Sanskrit: Candra-prabha) are two Bodhisattvas attending on either side of Medicine Buddha Lưu Ly Quang[1][2]. Nhật Quang is also called Nhật Diệu Bodhisattva or Nhật Quang Biến Chiếu Bodhisattva; Nguyệt Quang is also called Nguyệt Tịnh Bodhisattva or Nguyệt Quang Biến Chiếu Bodhisattva[1][2]. Their names are directly linked to the images of the Sun and Moon: Nhật Quang symbolizes the light of the Sun, Nguyệt Quang symbolizes the light of the Moon, both shining everywhere without any darkness[3].
What are the origins and scriptural records of Sunlight and Moonlight Bodhisattvas?
Medicine Buddha Sutra
The Medicine Buddha Sutra (藥師琉璃光如來本願功德經) was translated from Chinese by Tripitaka Master Huyền Trang[4]. In the sutra, after the Buddha introduces the Tịnh Lưu Ly realm in the East, He states: "於其國中，有二菩薩摩訶薩：一名日光遍照，二名月光遍照。是彼無量無數菩薩眾之上首，次補佛處，悉能持彼世尊藥師琉璃光如來正法寶藏"[4]. Translation: "In that realm, there are two Bodhisattvas Mahasattvas: one named Nhật Quang Biến Chiếu, two named Nguyệt Quang Biến Chiếu. They are the foremost among the countless Bodhisattvas, will successively take the Buddha's place, and can all uphold the Dharma treasury of the World-Honored One Medicine Buddha Lưu Ly Quang Tathagata"[4].
This shows their position is not only as left and right attendants but also as future successors of Medicine Buddha. The term "bổ xứ" (補處) in Chinese is a term for a Bodhisattva at the stage of one lifetime from Buddhahood[4].
Origin of the Medicine Buddha Sutra
According to the origin section of the sutra, once the World-Honored One traveled through countries, arrived at Quảng Nghiêm City, rested under the Âm Nhạc Tree, with a great assembly of monks and Bodhisattvas, kings, ministers, Brahmins, and laypeople. At that time, Mạn Thù Thất Lợi Dharma Prince (i.e., Văn Thù Sư Lợi Bodhisattva) asked the World-Honored One to teach the names and great vows of the Buddhas, so that beings hearing the Dharma might eliminate karmic obstacles[3]. The World-Honored One taught about the East, beyond ten Ganges sands of Buddha realms, there is a world named Tịnh Lưu Ly, whose teacher is Medicine Buddha Lưu Ly Quang Tathagata[3][4].
In this context, Nhật Quang and Nguyệt Quang are introduced as two Bodhisattvas attending on either side of Medicine Buddha in the Tịnh Lưu Ly realm[3][4].
What is the symbolic meaning of the two Bodhisattvas Sunlight and Moonlight?
Light of the Sun and Moon
The Tịnh Lưu Ly realm is described as completely pure, without any defilement, all adorned with precious jewels from deep merit. In that realm, the two Bodhisattvas Nhật Quang Biến Chiếu and Nguyệt Quang Biến Chiếu are likened to the light of the Sun and Moon shining everywhere; "Biến Chiếu" means shining to all places, nowhere without, nowhere dark[3].
This symbol has deep meaning: the Sun illuminates the day, the Moon illuminates the night, together covering all time and space, representing the wisdom and compassion of Buddhism never interrupted[3].
Connection with the Name Medicine Buddha
Dược Sư means "physician". In the world, a physician diagnoses, prescribes, and guides the sick to quick recovery. Medicine Buddha is likewise a great physician, knowing the three poisons of greed, anger, and delusion, seeing beings' evil paths, guiding those with ignorance to quickly heal mental suffering and return to the path of Dharma[3].
Lưu Ly is a gem that filters all impurities, "ly" means separation from defilement. Like a glass of muddy water, drop the Lưu Ly gem in, all dirt settles, returning clear water. The word Lưu Ly in Medicine Buddha's name shows the light of wisdom, helping all afflictions be cut off, returning to pure original mind[3]. Nhật Quang and Nguyệt Quang are the two powerful assistants of that great physician, together saving beings from suffering[3][4].
What are the forms and symbols of Sunlight and Moonlight in Esoteric Buddhism?
In the Kim Cương Giới Mandala
In the Kim Cương Giới Mandala, Nguyệt Quang Bodhisattva sits at the west side of the second hall in the Vi Tế assembly. Body white, left hand clenched at hip, right hand holds a bright moon or lotus with a half-moon on it. Secret name is Thanh Lương Kim Cương, samaya form is a half-moon[1].
In the Thai Tạng Giới Mandala
In the Thai Tạng Giới Mandala, Nguyệt Quang Bodhisattva sits to the right of Diệu Cát Tường Bodhisattva, between Diệu Âm Bodhisattva and Vô Cấu Quang Bodhisattva in the Văn Thù hall. Right hand clenched, holding a lotus at hip, on the lotus a half-moon; left hand holds a bud lotus at chest, sitting cross-legged on a lotus throne. Secret name is Uy Đức Kim Cương, samaya form is a blue lotus with a half-moon on it[1].
Nhật Quang Bodhisattva in the Thai Tạng Giới Mandala sits at the far west (bottom row) in the Trừ Cái Chướng hall. The Đại Nhật Sutra does not record this Bodhisattva, but in Huyền Pháp Tự Nghi Quĩ volume 2 and Thanh Long Tự Nghi Quĩ middle volume, He is placed in the Địa Tạng hall. His form: body flesh-colored, right elbow bent, hand upright and outward, middle, ring, and little fingers bent; left hand clenched at navel, holding a lotus with a pearl on it. Secret name is Uy Đức Kim Cương, samaya form is a red jewel[2].
Summary Table of Forms and Symbols
| Feature | Nhật Quang Bodhisattva | Nguyệt Quang Bodhisattva |
|---|---|---|
| Other names | Nhật Diệu, Nhật Quang Biến Chiếu | Nguyệt Tịnh, Nguyệt Quang Biến Chiếu |
| Sanskrit | Sùrya-prabha | Candra-prabha |
| Body color | Red (per Medicine Buddha Sutra); flesh-colored (per Thai Tạng Giới) | White |
| Attributes | Left hand holds Nhật luân (sun), right hand holds red flower garland | Hand holds moon or lotus with half-moon |
| Secret name | Uy Đức Kim Cương | Thanh Lương Kim Cương (Kim Cương Giới); Uy Đức Kim Cương (Thai Tạng Giới) |
| Samaya | Red jewel | Half-moon shape |
| Position in Mandala | Trừ Cái Chướng hall (Thai Tạng Giới) | Văn Thù hall (Thai Tạng Giới); Vi Tế assembly (Kim Cương Giới) |
What is the role of Sunlight and Moonlight in the Medicine Buddha Practice?
Foremost Among Bodhisattvas of Tịnh Lưu Ly
In the Medicine Buddha Sutra, the Buddha clearly states the two are "foremost among countless Bodhisattvas" of the Tịnh Lưu Ly realm, will successively take the Buddha's place, and can uphold the Dharma treasury of Medicine Buddha[1][4]. This places them at the center of Medicine Buddha faith: not only attendants but future heirs and maintainers of Medicine Buddha's teachings[4].
Assistants in Saving Beings
According to the Medicine Buddha Sutra, these two Bodhisattvas are foremost among countless Bodhisattvas who will successively become Buddhas[1]. Additionally, per Tu Dược Sư Nghi Quĩ Bố Đàn Pháp, Nguyệt Quang Bodhisattva has a white body, sits on a goose-shaped throne, holds the moon[1].
In Medicine Buddha practice, the two are often worshipped on either side of Medicine Buddha statue, forming a triad: Medicine Buddha in the center, Nhật Quang Bodhisattva on the left (or right depending on tradition), Nguyệt Quang Bodhisattva on the other side[1][2].
How to distinguish from other Bodhisattvas with the same name?
Note that in Buddhism there are many with the name Nhật Quang or Nguyệt Quang. According to Tự điển Phật học, Nguyệt Quang Bodhisattva also has another meaning: the name of a Buddha when practicing Bodhisattva in the past as a king[1]. This is a case of same name but different being, not to be confused with the attendant of Medicine Buddha[1].
Similarly, Nhật Quang Bodhisattva in the Thai Tạng Giới Mandala has Sanskrit Sùrya-prabhàsana (different from Sùrya-prabha of Medicine Buddha's attendant), and is called Nhật Quang Minh Bodhisattva[2]. This distinction shows the complexity of names in Esoteric Buddhism, same name can refer to different beings in different contexts[1][2].
What is the practical meaning of Sunlight and Moonlight Bodhisattvas?
In Vietnamese Folk Belief
In Vietnamese folk belief, images of Medicine Buddha with Nhật Quang and Nguyệt Quang often appear in Northern Buddhist temples, especially in Medicine Buddha halls or cầu an, health-praying altars[1][2]. People often pray to these Bodhisattvas for health, peace, and the light of wisdom[3].
In Practice
According to the spirit of the Medicine Buddha Sutra, worshipping and reciting the name of Medicine Buddha with Nhật Quang and Nguyệt Quang is not only for physical health but also for healing the three poisons of greed, anger, and delusion[3]. The two Bodhisattvas with Sun and Moon symbols remind practitioners that wisdom and compassion must illuminate day and night, uninterrupted, without darkness[3].
What is the conclusion about Sunlight and Moonlight Bodhisattvas?
Nhật Quang Bodhisattva and Nguyệt Quang Bodhisattva are important Bodhisattvas in the Medicine Buddha faith of Mahayana Buddhism. Scriptural sources like the Medicine Buddha Sutra translated by Huyền Trang, and Esoteric documents recording their forms and positions in Mandalas, affirm their foremost role in the Tịnh Lưu Ly realm[1][2][4]. Their Sun and Moon symbols are not just metaphors but reminders of the continuity of wisdom and compassion in practice[3].
