The cosmogony behind Kuniumi and Kamiumi:
Japan’s oldest historical record, the Kojiki. Chronicles of Ancient Matters, 712 CE), and the second oldest book of Japanese history, the Nihon Shoki. The Chronicles of Japan, 720 CE) are both full of Shinto (the polytheistic religion native to Japan) myths and legends. This includes cosmogony, or the creation story of the world and the universe. Few of the figures in the creation myth are rarely mentioned since the books were written, but some play important roles in other Japanese legends and Shintoism.
However, Japanese people don’t believe this anymore, the creation story is a good place to start if you’re interested in Japanese mythology and how it impacts Japanese culture. I’m going to tell that story in (hopefully) plain language. The creation myth is a little different in the Kojiki compared to the Nihon Shoki, but most people go by the Kojiki version, so that’s what I’ll be using.
Like many creation myths around the world, the universe started as silent chaos. Amidst this chaos, particles and light started to move. Light floated up faster than the particles, so the light is above the universe. The lighter particles floated up to form the clouds of takamagahara. The Plain of High Heaven). The heavier particles couldn’t float up, so they formed a mass called Earth below heaven.
When heaven was formed, five deities, the kotoamatsukami. The Separate Heavenly Gods) appeared. Three came into being before the last two and are known as the zouka-sanshin ( The Three Creation Gods). These five kami (, god or deity) were hitorigami (, Lone God) because they appeared spontaneously (as opposed to a male-female pair, which most gods are said to come from), didn’t have a partner, and were essentially gender-less. After these kami emerged, they went into hiding.
From there emerged the kamiyo-nanayo (, The Seven Generations of the Age of the Gods). Twice more hitorigami appeared, followed by five pairs of male-female kami. Also like many myths throughout the world, these pairs were husband and wife, but also brother and sister.
While there is an innumerable amout of kami now, the Japanese creation myth shows how the first 17, the 5 kotoamatsukami and the 12 kamiyo-nanayo, emerged. The last pair of the kamiyo-nanayo were Izanami (, She-Who-Invites) and her brother Izanagi (, He-Who-Invites). Izanagi and Izanami means two of the most important kami and are said to be the parents of hundreds to millions of other kami.
Both of Izanagi and Izanami were tasked by the elder kami with kuniumi (Birth of the Country). They went to ame-no-ukihashi (The Floating Bridge of Heaven) connected to Earth, which was still just a floating mass of water.
They churned the Earth with a jeweled spear, and the water that dripped off the tip of the spear when it was lifted created the first island, Onogoro-Shima (it is not known where this island is today).
Izanami and Izanagi then moved to the island and built a castle with a heavenly pillar on top of it; they circled the top of the pillar to get married, and created the ooyajima (Eight Great Islands), Awaji Island, Shikoku, Oki Islands, Kyushu, Iki Island, Tsushima Island, Sado Island, and Honshu. Other islands, like Hokkaido, and the rest of the world, were not mentioned as they were not yet known by the ancient Japanese.
After kuniumi, the kamiumi ( Birth of Gods) occurred. After creating the islands of Japan, Izanagi and Izanami birthed many kami, some male, some female, and some genderless. Giving birth to their last child, Kagutsuchi, the god of fire, Izanami was fatally injured. From her dying body some kami were born, and Izanagi’s tears while mourning her death birthed more kami. He was then so sad that he killed Kagutsuchi with a sword and cut him into 8 pieces, which created 8 volcanoes. Moreover, from Kagutsuchi’s body 8 more kami were born, and his blood on the sword and surrounding rocks created another 8 kami.
According to Shinto mythology, there is a land of the dead called yomi ( literally “yellow spring”; the real meaning of yomi is unknown in Japanese, but the writing came from Daoism). Izanagi went to yomi to bring Izanami back, but found out that she had already eaten food in yomi, which makes it incredibly hard for one to leave.
Izanami said that she will ask the gods of yomi if she could leave, but Izanagi would have to promise to not look at her, to which he agreed. She was taking a long time and Izanagi got worried, so he lit his comb from his hair to create some light in order to look for her. He eventually found her, but saw that her body was now a rotting corpse. He was scared, so he decided to abandon his wife and leave. Izanami was so embarrassed that her body bore eight thunder kami, and she commanded the yomotsu-shikome (female demons from yomi) to chase him.
When being chased, Izanagi threw his headress, which turned to grapes, and his comb, which turned into bamboo. Making the shikome stop to eat. Izanami then sent yomi warriors and the 8 thunder kami after him, but Izanagi threw three peaches at them. So they ran away (peaches were thought to have evil-banishing magic at the time).
At the slope that connects the land of the dead and the land of the living, Izanami and Izanagi met. And Izanagi lifted a huge rock and blocked the path (which is said to be in Matsue, Shimane Prefecture). Izanami yelled over the rock and said that if he leaves her she will kill 1,000 people. Every day, to which Izanagi replied by saying that he will ensure that 1,500 be born every day. That was the last time they saw each other, dissolving their marriage with Izanagi becoming. The ruler of the living and Izanami becoming the ruler of the dead.
After leaving yomi, Izanagi decided to perform misogi (, a Shinto purification ritual) in a river to cleanse himself. Performing this ritual created 23 kami; the last step of the ritual created an additional 3 kami, known as the mihashira no uzu no mikoto. (Three Precious Children), the three most important kami in Shintoism. Amaterasu (roughly means ‘The Light of Heaven’), the female goddess of the sun. Was born from the washing of Izanagi’s left eye. Tsukuyomi ( roughly means ‘Reader of the Moon’). The gender-less deity of the night, was born from the washing of his right eye. Finally, Susano’o (probably means ‘the man/male god from Susa’), the male god of the seas and storms. Was born from the washing of his nose. This is why we wash our hands at the entrance of shrines and temples. To cleanse ourselves before entering a sacred place.
These myths explained how the universe and kami came to be, creating the basis for other Shinto stories and beliefs. The story of Izanagi and Izanami, along with stories about Amaterasu and Susano’o, are some of the most well known.
The Japanese mythology has many such interesting tales. It can be equated with the Sindhu mythology as well.