Japanese Buddhist goddess who originated from the Hindu goddess Saraswati
Benzaiten ("shinjitai": 弁才天 or 弁財天; "kyūjitai": 辯才天, 辨才天, or 辨財天, lit. "goddess of eloquence", Benten, Chinese: 辯才天, Biancaitian) is an East Asian Buddhist goddess (technically a Dharmapala, "Dharma protector") who originated mainly from the Buddhist Indian Saraswati, goddess of speech, the arts, and learning. Worship of Benzaiten arrived in Japan during the sixth through eighth centuries, mainly via Classical Chinese translations of the "Golden Light Sutra" (Sanskrit: "Suvarṇaprabhāsa Sūtra"), which has a section devoted to her., and there are several Shinto shrines dedicated to her.
As such, Benzaiten is now also associated with dragons, snakes, local Japanese deities, wealth, fortune, protection from disease and danger, and the protection of the state.
Indian deity.
Saraswati (Sanskrit: "Sarasvatī"; Pali: "Sarassatī") was originally in the "Rigveda" a river goddess, the deification of the Sarasvati River. She was identified with Vach (Skt. "Vāc"), the Vedic goddess of speech, and from there became considered to be the patron of music and the arts, knowledge, and learning. 
In addition to their association with eloquence and speech, both Saraswati and Vach also show warrior traits: Saraswati for instance was called the "Vritra-slayer" ("Vṛtraghnī") in the "Rigveda" (6.61.7) and was associated with the Maruts. She was also associated with the Ashvins, with whom she collaborates to bolster Indra's strength by telling him how to kill the asura Namuchi. In a hymn in Book 10 of the "Rigveda" (10.125.6), Vach declares: "I bend the bow for Rudra that his arrow may strike and slay the hater of devotion. I rouse and order battle for the people, and I have penetrated Earth and Heaven."
Saraswati, like many other Hindu deities, was eventually adopted into Buddhism, figuring mainly in Mahayana texts. In the 15th chapter of Yijing's translation of the "Sutra of Golden Light" ("Suvarṇaprabhāsa Sūtra") into Classical Chinese (Taishō Tripitaka 885), Saraswati (大辯才天女, pinyin: "Dàbiàncáitiānnǚ"; Japanese: "Daibenzaitennyo", lit. "great goddess of eloquence") appears before the Buddha's assembly and vows to protect all those who put their faith in the sutra, recite it, or copy it. In addition, she promises to increase the intelligence of those who recite the sutra so that they will be able to understand and remember various "dharanis". 
She then teaches the assembly various mantras with which one can heal all illnesses and escape all manner of misfortune. One of the Buddha's disciples, the brahmin Kaundinya, then praises Saraswati, comparing her to Vishnu's consort Narayani (Lakshmi) and declaring that she can manifest herself not only as a benevolent deity, but also as Yami, the sister of Yama. He then describes her eight-armed form with all its attributes — bow, arrow, sword, spear, axe, vajra, iron wheel, and noose. 
The poem describes Saraswati as one who "has sovereignty in the world", as one who is "good fortune, success, and peace of mind". It also states that she fights in battlefields and is always victorious. 
One key concern of the "Golden Light Sutra" is the protection of the state, and as such, Saraswati here also takes on some form of a warrior goddess, similar to Durga. Bernard Faure also notes that the Vach already had martial attributes, which may have been retained in some form.
Bencaitian / Benzaiten.
Saraswati became the Chinese 辯才天 (Bencaitian) or "great eloquence deity" (大辯天). This became the Japanese 弁財天 (Benzaiten). In East Asian Buddhism, she is one of the Twenty-Four Protective Deities (Chinese: 二十四諸天; pinyin: "Èrshísì Zhūtiān"). She remained associated with wealth, music, and eloquence and also took on aspects of a fierce protector of the state (due to the influence of the "Golden Light Sutra" which promises to protect a country where the sutra is chanted).
During the medieval period onwards, Benzaiten came to be associated or even conflated with a number of Buddhist and local deities, including the goddess Kisshōten whose role as goddess of fortune eventually became ascribed to Benzaiten in popular belief). As such, she was eventually also worshiped as a bestower of monetary fortune and became part of the set of popular deities known as the Seven Lucky Gods ("shichifukujin").
Benzaiten is depicted a number of ways in Japanese art. She is often depicted holding a "biwa" (a traditional Japanese lute) similar to how Saraswati is depicted with a veena in Indian art, though she may also be portrayed wielding a sword and a wish-granting jewel ("cintāmaṇi"). An iconographic formula showing Benzaiten with eight arms holding a variety of weapons (based on the "Golden Light Sutra") meanwhile is believed to derive from Durga's iconography. As Uga Benzaiten, she may also be shown with Ugajin (a human-headed white snake) above her head. Lastly, she is also portrayed (albeit rarely) with the head of a snake or a dragon. 
Benzaiten's worship also spread to Taiwan during the Japanese colonial period, and she is still venerated in certain locations in Taiwan, such as the Xian Dong Yan temple in Keelung City.
Syncretism with Shinto kami.
Due to her status as a water deity, Benzaiten was also linked with "nāgas", dragons, and snakes. Over time, Benzaiten became identified with the Japanese snake "kami" Ugajin. She also became identified with the "kami" Ichikishima-hime. 
Benzaiten was also adopted as a female "kami" in Shinto, with the name . This kami is one of three "kami" believed to be daughters of the sun goddess Amaterasu, the ancestress of the imperial family.
She is also believed by Tendai Buddhists to be the essence of the "kami" Ugajin, whose effigy she sometimes carries on her head together with a "torii" (see photo below). As a consequence, she is sometimes also known as Benzaiten or Uga Benten.
Bīja and mantra.
The "bīja" or seed syllable used to represent Benzaiten in Japanese esoteric Buddhism is ' (सु, traditionally read in Japanese as so""'), written in Siddhaṃ script.
In Japanese esoteric Buddhism (mikkyo), Benzaiten's main mantra is as follows: 
Temples and shrines.
In Japan, the places of worship dedicated to Benzaiten are often called "辯天堂" (benten-dō) or . Shinto shrines dedicated to her are also called by this name. Entire Shinto shrines can be dedicated to her, as in the case of Kamakura's Zeniarai Benzaiten Ugafuku Shrine or Nagoya's Kawahara Shrine. Benzaiten temples or shrines places are commonly located near bodies of water like rivers, ponds, or springs due to her association with water. Benzaiten's worship became integrated with native Japanese beliefs, including serpent and dragon symbolism, as she was originally a river goddess. 
Benzaiten is enshrined on numerous locations throughout Japan; for example, the Enoshima Island in Sagami Bay, the Chikubu Island in Lake Biwa and the Itsukushima Island in Seto Inland Sea (Japan's Three Great Benzaiten Shrines); and she and a five-headed dragon are the central figures of the Enoshima Engi, a history of the shrines on Enoshima written by the Japanese Buddhist monk Kōkei (皇慶) in 1047. According to Kōkei, Benzaiten is the third daughter of the dragon-king of Munetsuchi (無熱池; literally "lake without heat"), known in Sanskrit as Anavatapta, the lake lying at the center of the world according to an ancient Buddhist cosmological view.
Ryōhō-ji, also known as the "Moe Temple", enshrines Benzaiten. It is famous for anime style depictions of Buddhist deities.
Shinto shrines enshrining Benzaiten.
Benzaiten is also enshrined as Ichikishima Hime-no-Mikoto at the Munakata Taisha shrine.
References.
 ;templatestyles src="Reflist/styles.css" / ;