Yes it is true. The historical Hayato people of Japan, as well as the Kumaso and Azumi tribes, were of Austronesian origin and closely related to the indigenous people of Taiwan.
These groups are also known as the “Sea people”, which were active in Japan and the Ryukyuan Islands before and during the Yayoi period. I.e. also during the late Jōmon period.
They are generally agreed to have been largely Austronesian in origin, but some proposed that there were also Austroasiatic and Kra-Dai tribes among them.
Historical stories including crocodiles, snakes and various kind of fish further links them to Austronesians of Taiwan.
Some general information:
The Hayato (隼人), which is Japanese for "falcon-people", were a people of ancient Japan who lived in the Satsuma and Ōsumi regions of southern Kyushu during the Nara period. They frequently resisted Yamato Japanese rule. After their subjugation they became subjects of the government under Ritsuryō, and the Ministry of the Military had an office known as the Hayato-shi (隼人司) in charge of their governance.
(Native Taiwanese were closely related to the Austronesian tribes of Japan.)
The Hayato are recorded in various historical texts until the beginning of the Heian period. They are listed among the attendants of emperors and princes from as early as Emperor Nintoku's reign. This, along with a mention of Hayato crying before the grave of Emperor Yūryaku after his death, suggests that the Hayato were naturalized as personal servants by the late 7th century.
Even after pledging allegiance to the Japanese court, the Hayato continued to resist its rule. After the establishment of Ōsumi Province in 713, the Ōsumi Hayato fought back in 720 with the Hayato Rebellion, but were defeated in 721 by an army led by Ōtomo no Tabito. The Handen-Shūju system was implemented in their lands in 800. The population of Yamato immigrants in Kagoshima prefecture in the early 8th century has been estimated at around 9,000 people and one-seventh of the total population. By this estimate, the Hayato population of the time can be calculated as consisting of around 54,000 people (not including Hayato emigrants to Honshū).
The Hayato were made to emigrate to the Kinai region, and were active in the protection of the court, the arts, sumo, and bamboo work. Many lived in Yamashiro Province, in the south of modern Kyoto. There remains an area called Ōsumi (大住) in Kyōtanabe, Kyoto, where many Ōsumi Hayato lived. These were the Hayato governed by the Hayato-shi.
Their culture was also unique from those of other regions of Japan. In particular, their folk song and dance became famous in the Kinai region as the Hayato dance (隼人舞). An excavation of Heijō Palace discovered wooden shields with a distinctive reverse-S-shaped marking. These shields match those described in the Engishiki, which the Hayato used in court ceremonial functions. The Hayato had roles in various state ceremonies, including those for the new year, imperial enthronement, and visiting foreign officials.
According to the ancient records of Hizen province, the Gotō Islands were also inhabited by a people resembling the Hayato. The New Book of Tang describes a minor king of Haya (波邪), and this Haya has also been interpreted as referring to the Hayato.
The linguistic material we have about the Hayato people suggests that they are of the Formosan branch of the Austronesian languages, i.e close to the Native Taiwanese languages.
Similarly, the Azumi people are also of Austronesian origin.
The Azumi (阿曇氏 or 安曇族) were a warrior clan and tribe during the Jōmon period in Japan, whose cultures and beliefs are considered to be one of Japan’s earliest sea religions. Their existence dates back to the early 3rd – 7th centuries, when their extensive knowledge of navigation between waters made them the naval force of Yamato Japan. They lived in Northern Kyushu, especially in an area called Chikuzen, now part of modern-day Fukuoka Prefecture. Their knowledge and ability to use tidal changes, weather patterns and star constellations ensured their successful routing and voyaging on the sea during their regular exploration. In essence, the working of Azumi life was centred around their sea God, Watatsumi and their omnipotent deity ‘Isora’, who provided the Azumi people with a strong sense of spiritual guidance throughout their day to day life.
They were the oldest group and leaders of the “Ama”, a group of people who navigated the waters of West Japan (Tsushima), Korea and China. They also performed trade with China and Korea and were responsible for the transport of iron from the Korean Peninsula to Northern Kyushu. According to some historians, the Azumi were "the oldest known maritime force of Japan's emerging imperial state." I.e. all these Austronesian tribes got completely absorbed into the Yamato Japanese.
The Azumi people were extremely skilled seafarers and their extensive knowledge of water currents, tidal changes, weather and star constellations is believed to have been passed down from generation to generation. Their ability to navigate the seas, especially at night, made them useful to the Japanese imperial government during the 3rd to early 5th centuries and they were effectively the naval force of Yamato Japan. With the new responsibility and accountability accorded to them, the Azumi people became the biggest influence in controlling the various Inland Sea routes to Kyushu along the Inland Coast. In this role, it was the Grand General of the naval force who was in charge of protecting these seas.
Azumi no Hirafu, a member of the Azumi tribe, was appointed this role as Grand General when the emperor sighted him along with a group of men swimming toward their boat on the Inland Sea. These men wore deer antlers covering their heads, appearing as a close herd of deer on the seas. In the ancient beliefs of Shintoism, deer were believed to be spiritual messengers, or specifically ‘Messengers to God’. Today in Nara, the modern capital of Japan, this belief and symbolism of the deer has continued, as over one thousand deer freely roam the Kasuga Grand Shrine, remaining intrinsically linked with both the kami revered there and the descendants of the Azumi.
Before voyaging, the Azumi people often performed rituals of sea-worship to the oceanic deities as they believed this assisted them to establish control and territory in various regions of the sea. However, when they faced defeat at the Bay of Hakunsonko in 633, Azumi no Hirafu, along with other members of the Azumi tribe spread along to the various regions of Japan, with the majority leaving the straits of northern Kyushu. In these voyages, they became involved in other specialities and traditions. One of these roles included preparing and tasting imperial food, otherwise known as “Saba”. Under the Japanese legal system of Ritsuryō, they became affiliated with the department of the Ministry of the Imperial Household responsible for preparing the emperor's food, largely because of their historic role of providing seafood to the imperial state. The Azumi became prominently known for specialising in preparing imperial meals later in the clan's history as this formed as an additional part of the responsibility that they owed the imperial government.
Although some of the Azumi people stayed and continued the traditional life as sea goers, for those who decided to leave sea life, many ended up on the small island of Shinshu, where they became heavily involved in farming and agriculture. During these times, even though they were no longer seafarers, it is believed that they still maintained their intrinsic connection to their past ancestors through regularly praying to the deity Isora, thankful for the water which flowed from Kamikochi’s mountains granting them successful crop irrigation.
The Azumi people who did not choose to engage with the farming lifestyle in Shinshu ended up in the Azumi Basin. Here, they formed a small fishing village and developed their language, continuing to practice their core spirituality to the deity Isora. Over time, they became known as “the people who lived at the sea.”
In the late 7th Century, the Azumi people also had a key role in maintaining peace for the Yamato Court’s maritime and became core allies in warfare. However, this rapport became troubled during the ‘Tenumu Reign’ in 682. Emperor Tenumu invaded South Kyushu, but instead of inflicting war on the Yamato Court, they offered tokens of their gratitude in appreciation of the Azumi people’s comradery and supposed obedience to them. This gesture confused the Yamato Court, and led them to doubt and question the loyalty of the Azumi People. The ruling dynasty banished the Azumi sometime before the 8th century.
Today, the places to which the Azumi people voyaged to have been named after their presence (Kakojima, Kagoshima, Kashima, Shikashima) and there are still traces of their existence remaining in the areas they commonly voyaged through (Islands of Tsushima Straits, Kyushu, Shikoku, Awaji Islands).
According to Japanese historians, they were of Austronesian origin and related to the Hayato people. They were in early contact with the Yamato court, providing important maritime trade links to the Japanese capital and influencing the court's military and diplomatic efforts at sea. Some Azumi migrated further inland, settling in what is now known as Azumino Valley or Azumi Basin in Nagano prefecture. They also spread toward the imperial center, settling in Settsu province around what is now Osaka. Remnants of Azumi culture are also found on Awaji Island in Hyogo prefecture.
Being the leading tribe during the Yayoi period, the Azumi held the common belief of a deity who would allow for safe navigation of rough seas if prayed to before embarking on a sea journey. This deity, known as ‘Azumi no Isora’ is placed at the centre of the Azumi tradition and is believed to embody the seas which surround Japan. I.e. the Azumi as well as the Hayato people are among the Jōmon period tribes which successfully survived and influenced the ancient Japanese people, giving rise to modern Japan. Thus, Austronesian influence in Japan is an indisputable fact.
See also:
Austronesian Architectural Heritage and the Grand Shrines at Ise, Japan | Semantic Scholar
Austronesia, one of the largest language families in the world, covers a vast area from Madagascar in the extreme west to Easter Island in the far east, Taiwan in the north to New Zealand in the south. The languages are spoken by the people of insular southeast Asia, Micronesia, Melanesia and Polynesia in the Pacific, as well as certain parts of the Asia mainland. The vernacular architecture of the people that belong to this language family shows certain shared characteristics that seem to indicate a common origin in the distant past. The Grand Shrines at Ise, Japan pose an intriguing phenomenon because they possess striking architectural features that are reminiscent of Austronesian vernacular architecture. This paper is an attempt to investigate the phenomenon using the findings of studies by experts from other disciplines such as historians, anthropologists, linguists and others, based on the link between culture, language and architecture.1
Influence on local Shinto:
‘Azumi no Isora’ is also believed to emerge during the Muromachi period, around the same time as three similar Watatsumi deities: Sokotsu, Uwatsu and Ojin. These three deities, once representing the seas that surround Japan, were said to infuse into a single being known as Isora. The spirit of Isora is represented as a seahorse, and is considered a symbol of purity, providing spiritual guidance to the Azumi people throughout their day to day life.
Additionally, Azumi no Isora is suggested to be the primordial human ancestor as it was him that first performed the dance ritual known as “Sei-no-no” (also known as Seino and Kuwashi-O). The dance was believed to be performed in two parts with a dialogue intermission in between, spoken by two characters: the deity Isora and the goddess Toyo. In the dialogue, Isora is described to be an old man with white hair. “Sei-no-no” consists of four male dancers: two with small drums to accompany their movements and two without. All four were described to have a white cloth covering their face, dancing along in the night to the melody of flutes.
This dance has been passed down through Azumi tribe generations as a ritualistic way to explore their connection to Azumi no Isora and express their praise. It was also performed with the shells of sea turtles by the ‘Urabe Diviners’ (the first adherents of Azumi no Isora) as a gateway to determine which days were safe for voyages to sea. Additionally, the Azumi people’s kinship to the Urabe Diviners and their history is symbolised by three deity stones in the shape of a sea turtle.
Today, there are multiple shrines which are dedicated to the Azumi People. There is one in Genkai Bay on Shikanoshima Island dedicated to Azumi no Isora which contains sacred stones to represent the sea turtles, as well as over a thousand deer antlers to maintain their relationship with the deities. There is another on the north side of Japan known as the Hodaka shrine. This ritualistic shrine is thought to be a ‘mini-museum’, solely dedicated to preserving the rich culture and history of the Azumi People.
The Austronesian Azumi/Hayato people, next to the Japonic Izumo people, were serious rivals towards the Japonic Yamato. If history would be slightly different, Japan may now speak a Austronesian language, and the dominant ethnic group would be known as Azumi. The culture would likely be similar, but with even more cultural and mythological links towards Native Taiwanese and other Austronesian peoples of Southeast Asia.
(Ethnic Malays, an Austronesian ethnic group of Insular Southeast Asia.)
