Ryokai-mandala (Mandala of the two Realms) (両界曼荼羅)
Ryokai-mandala is a mandala which visually depicts the truth and the state of enlightenment that is advocated by Dainichi Nyorai (Mahavairocana), principal Buddha in Esoteric Buddhism. Mandala is the one where many 'Buddha,' including Dainichi Nyorai, are arranged in accordance with a certain fixed order and two mandala, namely Garbha-mandala (also called Taizokai-mandala) and Vajradhatu-mandala, are collectively called Ryokai-mandala or Ryoubu mandala. Other than the ones which depict the individual image of Buddha in paintings, some depict one Buddha symbolically by one Sanskrit character (a kind of letter which was used for writing Sanskrit).
Origin of Ryokai-mandala and its Introduction into Japan
Garbha-mandala (Daihitaizosho mandala) is drawn based on Esoteric Buddhism scriptures called 'Daibirushana Jobutsu Jinbenkaji-kyo Sutra' (Mahavairocana Sutra) and Vajradhatumandala is drawn based on Esoteric Buddhism scriptures called 'Kongocho-kyo' (Vajrasekhara Sutra). Dainichi-kyo Sutra (Mahavairocana Sutra) is believed to have been established in India in the middle of the 7th century and it was translated into Kanji characters (translated into the then Chinese language) around 725 in the early 8th century by Zenmui (683 - 735), a native Indian monk, along with his disciple Ichigyo (683 - 727). On the other hand, Kongocho-kyo Sutra is believed to have been established in India during the period from the end of 7th century to early 8th century and was translated into Kanji characters around the same time with the translation of Dainichi-kyo Sutra by Kongochi (671 - 741), a native Indian monk, along with his disciple Fuku (705 - 774). Although the volume of Kongocho-kyo Sutra is so huge since it compiled all the teachings that Dainichi Nyorai advocated on 18 various occasions, collectively called Jyuhachi-e, the one which Kongochi and Fuku translated is the teachings advocated on the first occasion, called Sho-e, only. The teachings at Sho-e are called Shinjitu Sho-gyo Sutra (attva-samgraha).
At any rate, despite the fact that both 'Dainichi-kyo Sutra' and 'Kongocho-kyo Sutra' share Dainichi Nyorai as their common principal Buddha, these two are scriptures of different lineage which were established independently in different regions of India at different times and were introduced into China separately. It is presumed that Eka (746 - 805), a monk in the Tang dynasty period and who was Kukai's mentor, integrated the teachings of two scriptures into Ryokai-mandala. As Eka thought it impossible to orally transmit the in-depth teachings of Esoteric Buddhism, he made a Tang painter draw Ryokai-mandala and gave it to Kukai. Kukai took back such mandala when he returned to Japan in 806 after finishing his study in Tang.
Although the originals which Kukai took back were lost, a copy which is believed to be quite similar to the original is preserved at Jingo-ji Temple in Kyoto, known as national treasury Ryokai-mandala (commonly called Takao-mandala). Mandala at Jingo-ji Temple is not a colored one but one drawn with ground gold and silver on a woven purple material.
Composition of Garbha-mandala
Garbha-mandala is called Daihitaizosho mandala to be precise and although the term that indicates 'world' is not included in the original language, it has been called 'Taizokai mandala' from long ago in tune with Vajradhatumandala,.
The mandala is divided into 12 parts of 'in' (sections). What is located in the center is 'the central eight-Petal Court' and Taizokai Dainichi Nyorai (who is in a posture of 'Hokkai Join' (Dharma-realm meditation mudra) folding both hands in front of the belly) is sitting on the center of a lotus flower with 8 petals. Around Dainichi Nyorai, all 8 statues, namely 4 of Nyorai (Hodo (Ratnaketu Tathagata), Kaifukeo (Samkusumitaraja), Amida Nyorai (or Muryoju, Amitabha Tathagata) and Tenkuraion (Divyadundubhimeghanirghosa)) and 4 of Bosatsu (Fugen bosatsu (Samantabhadra Bodhisattva), Monju Bosatsu (Manjusri), Kannon Bosatsu (Kannon Buddhisattva) and Miroku Bosatsu (Buddha of the Future, Bodhisattva of the Present), are depicted.
As for the naming of mandala, both Taizokai-mandala and Garbha-mandala are used in Japan but Motohiro YORITOMI, a researcher of Esoteric Buddhism, wrote in his book titled "Architectures of mandala-centering on mandala at To-ji Temple" as 'the name of mandala were created in consideration of both Dainichi-kyo Sutra and Kongocho-kyo Sutra, collectively called Ryobu Sutra and both are the source of mandala, and Kukai used only this name (note: Ryobu-mandala),' 'because Kongocho-kyo Sutra clearly uses Vajradhatumandala, Dainichi-kyo Sutra does not use the name of Taizokai-mandala though it uses Daihitaizosho mandala or Garbha-mandala.'
Motohiro YORITOMI further asserts that with the development of Tendai Esoteric Buddhism (Daimitsu) thanks to Ennin, Enchin and Annen, the term of 'Taizokai' (the Womb Realm) was widely used in the text for prayer and austerities and as a result, the terms of Ryokai-mandala and Taizokai-mandala came into use.
The central eight-Petal Court is surrounded by Henchi-in, Jimyo-in, Shaka-in (Court of Shaka Nyorai), Kokuzo-in (Court of Kokuzo Bosatsu (Akasagarbha Bodhisattva), Monju-in (Court of Monju Bosatsu (Manjusri)), Soshituji-in, Rengebu-in, Jizo-in (Court of Jizo Bosatsu (Jizo Bodhisattva)), Kongoshu-in and Jogaisho-in in a concentric fashion and Gekongobu-in, also called Saige-in, is located at the outer circumference that encircles all of the above. This suggests the movement from the inner side to the outer side and represents the transformation of Dainichi Nyorai's abstract wisdom into practice in the real world.
Further, Garbha-mandala should be seen by dividing it into three blocks, namely center, right and left block.
The center block represents the world of Dainichi Nyorai's state of enlightment while Rengebu-in (Kannon-in), whose principal statue is Shokanjizai Bosatsu (Kannon Bosatsu), is located on the observers' left (south in terms of direction) and Kongoshu-in (Kongobu-in or Satta-in), whose principal statue is Kongosatta, is located on the observers' right (north in terms of direction). It is believed that Rengebu-in represents Nyorai's 'mercy' and Kongoshu-in represents Nyorai's 'wisdom' respectively.
Composition of Vajradhatu-mandala
While each block of Garbha-mandala is called 'in,' the term of 'E' is used in the case of Vajradhatu-mandala and it consists of Ku-e (nine e), namely Jojin-e, Samaya-e, Misai-e, Kuyo-e, Shiin-e, Ichiin-e, Rishu-e, Gozanze-e and Gozanze Samaya-e. This should be understood as the aggregate of 9 mandala rather than 9 blocks.
The principal statue of Jojin-e, which is located in the center, is Kongokai Danichi Nyorai (who is in a posture of 'Chiken-in' (the knowledge-fist mudra) with wrapping the forefinger of left hand by the fist of right hand). Ashuku Nyorai, Hosho Nyorai (Ratnasambhava, one of the Five Wisdom Buddhas), Amida Nyorai and Fukujoju Nyorai (Amoghasiddhi, one of the Five Wisdom Buddhas) are located at the east, south, west and north of Dainichi Nyorai respectively (Dainichi, Ashuku, Hosho, Amida and Fukujoju are collectively called Kongokai-gobutsu or Gochi-nyorai). At the east, south, west and north side of each Nyorai, Bosatsu that are closely related to each Nyorai, called Shishingon Bosatsu (Four Attendant Bodhisattva), are located.
Samaya-e, Misai-e and Kuyo-e have almost the same composition as that of Jojin-e located in the center and it is no mistake that Shiin-e is the simplified version of the above and Ichiin-e is the one which omits other Buddha than Dainichi Nyorai. The principal statues of Rishu-e, Gozanze-e and Gozanze Samaya-e, which are located at the right side of mandala, are not Dainichi Nyorai but Kongosatta for Rishu-e and Gozanze Myoo (Trailokya-vijaya) for the other two. Kongosatta, who is counted as one of the Bosatsu, and Gozanze Myoo, who has a fierce look, are believed to be the reincarnation of Dainichi Nyorai after attaining the state of enlightment and this depiction represents the belief that everything derives solely from Dainichi Nyorai.
It is perceived that while Garbha-mandala grasps the truth as matter of the real world from practical aspects, Vajradhatu-mandala grasps the truth as the matter of spiritual world from theoretical aspects.