Hinduism in a narrow sense is a polytheism that has been gradually formed while inheriting the scriptures and caste system from Brahmanism and absorbing indigenous gods and worship patterns. Around 2000 BC Aryans invaded northwestern India from Iran. They established the Veda around 1500 BC and worshiped Brahmanism based on it.
Due to political changes and the rise of Buddhism around the 5th century BC, Brahminism was forced to change. As a result, Brahminism accepts and assimilates folk religions and changes to Hinduism. (There is also the idea that Brahminism is also included in Hinduism.) Hinduism began to emerge in the 5th-4th century BC, and in the 4th-5th century BC, it came to surpass Buddhism which was dominant at the time. Since then, it has been revered by the people as an Indian religion.
It is a religion that has a unique concept of reincarnation and liberation as well as belief in the gods, and is characterized by a lifestyle typified in the four-dwelling periods and a caste system that includes status (Varna) and occupation (Jati).
In the modern doctrine called the Triumph, the three main deities, namely
Brahma: The universe, the God who gives the world a real, existential place
Vishnu: The god of the universe, maintenance of the world, peace
Shiva: God who creates the universe, the world, and destroys and ruins when its life ends, are said to be one. However, nowadays, the number of people who worship Brahma is reduced, and Vishnu and Shiva are listed as two major gods, and there are many believers. The group that believes in Vishnu is called Vishnu, and the group that believes in Shiva is called Shiva.
Hindu gods and rituals have changed shape, but they have influenced Buddhism in Japan.