A messenger arrived in the heavenly realm of Takamagahara with news that would break the sun. Tsukuyomi-no-Mikoto, the moon god, had killed the earth goddess Ukemochi. He had been sent by his sister Amaterasu to pay a courtesy visit. What he saw there repulsed him so deeply that he drew his sword. When Amaterasu learned what her brother had done, she spoke a sentence that would separate day from night forever: “I will never look upon your face again.”
The relationship between Amaterasu and Tsukuyomi is one of permanent estrangement between siblings, defined by a single act of violence that split the sun and moon into opposing realms. Their story, recorded in the eighth-century Kojiki, explains why the sun and moon never share the sky and why Shinto honors them in separate rites.
Where the Story Begins: The Kojiki and Nihon Shoki
The oldest surviving Japanese chronicles, the Kojiki (712 CE) and the Nihon Shoki (720 CE), preserve the myth. In the Kojiki, the account is terse. Amaterasu Omikami, the sun goddess and ruler of Takamagahara, sends her brother Tsukuyomi to visit Ukemochi, a goddess of the earth. Ukemochi welcomes him by producing food from her mouth, nose, and anus: rice, fish, and game. Tsukuyomi finds the method so offensive that he kills her on the spot.
The Nihon Shoki expands the scene. Ukemochi is identified as a daughter of the primordial pair Izanagi and Izanami. Her death is not simply a murder; it becomes the origin of cultivated plants. From her corpse spring millet, rice, beans, and silkworms. Amaterasu, upon hearing of the killing, is not grateful for the crops. She is furious. “You are an evil deity,” she declares, and banishes Tsukuyomi from her sight.
From that moment, the sun and moon are separated. They occupy opposite sides of the sky. One rises as the other sets.
The Birth of the Siblings: Izanagi’s Purification
To understand the weight of this estrangement, we must go further back. Amaterasu and Tsukuyomi are not simply siblings. They were born from the same act of purification.
After Izanagi escaped the underworld of Yomi, he bathed in a river to cleanse himself of its corruption. As he washed his left eye, Amaterasu emerged. From his right eye came Tsukuyomi. From his nose came Susanoo, the storm god. This triple birth placed the sun and moon as equals in origin, both children of the same divine father, both assigned realms of the sky. Amaterasu received the heavens. Tsukuyomi received the night.
The Nihon Shoki adds that Izanagi gave Tsukuyomi dominion over the “realm of the night,” while Amaterasu ruled the “plain of high heaven.” They were meant to govern complementary spheres. The myth of Ukemochi shattered that complementarity.
Symbolism: What the Separation Means
The estrangement is not a war. Amaterasu does not attack Tsukuyomi. She refuses to see him. This is a withdrawal of presence, not a battle. The moon is not a defeated enemy. He is a brother who committed an unforgivable act.
In Shinto cosmology, the sun and moon are not equal opposites in the way that light and darkness are often framed in Western traditions. Amaterasu is supreme. She is the ancestor of the imperial line, the source of life, the ruler of the heavens. Tsukuyomi is secondary, a figure of absence. His light is borrowed. His domain is the night, which in early Japanese thought was associated with death, spirits, and the uncertain boundary between worlds.
The myth also carries a moral weight. Tsukuyomi’s disgust at Ukemochi’s method of producing food is a failure of perspective. He judged by appearance, not by the gift. Amaterasu’s reaction is both righteous anger and grief. She does not kill him in return. She severs the relationship. The sun and moon will never again meet face to face.
Some later commentaries, including the Engishiki (927 CE), a collection of Shinto rituals, note that Tsukuyomi is not inherently evil. He is simply estranged. Shrines dedicated to him exist, but they are few. His worship is quiet, often conducted at night or in shadowed groves.
Practices and Traditions: How Shinto Honors the Schism
The separation is not merely a story. It is enacted in ritual.
Amaterasu is enshrined at the Ise Grand Shrine, the most sacred site in Shinto. The shrine faces south, toward the sun’s path. Priests perform daily offerings of rice, sake, and mirrors. The imperial family traces its lineage directly to her.
Tsukuyomi has no equivalent national shrine. The most prominent is Tsukuyomi Shrine in Kyoto, built in the Heian period (794–1185 CE). Its main hall faces west, away from the sunrise. Offerings are made at night, often by moonlight. In some local traditions, the shrine is closed during the day.
We find a striking practice in the Kojiki itself: the myth is recited during certain purification rites, particularly those involving boundaries. The separation of sun and moon becomes a template for separation of sacred and profane, of life and death. In the Norito (Shinto prayers), Amaterasu and Tsukuyomi are never invoked together in the same prayer. To do so would be to force a meeting that the myth forbids.
Some folk traditions hold that eclipses are moments when the siblings briefly glimpse each other. But this is not found in the classical texts. The Kojiki and Nihon Shoki are silent on eclipses. The separation is absolute.
Comparisons: Sibling Pairs in Other Mythologies
The closest parallel in another pantheon is the Greek Apollo and Artemis, twin siblings of sun and moon. But Apollo and Artemis are not estranged. They cooperate, hunt together, and share temples. The Egyptian Ra and Thoth are not siblings. The Norse Sol and Mani are siblings but are chased across the sky by wolves, not separated by choice.
The Japanese myth is unique in that the separation is a direct consequence of a moral failure. Tsukuyomi’s disgust is a sin of perception. He saw impurity where there was sacred generosity. Amaterasu’s refusal to see him is a judgment that cannot be undone.
Some scholars, such as the folklorist Kunio Yanagita (1875–1962), argued that the myth reflects an ancient taboo against looking at the dead or at bodily functions. Tsukuyomi’s act of killing Ukemochi is itself a violation of hospitality. The relationship between sun and moon becomes a cautionary tale about the consequences of breaking sacred bonds.
Common Misconceptions
They are not enemies. Estrangement is not warfare. Tsukuyomi does not attack Amaterasu, nor does she seek revenge. She simply refuses to see him.
Tsukuyomi is not evil. He is impulsive and disgusted, but the texts do not label him as a demon or a villain. His act is wrong, but he is not cast out of the pantheon. He remains a kami, worshipped in his own right.
They are not married. Some modern retellings romanticize the sun and moon as lovers. The classical sources are clear: they are siblings, born from Izanagi’s eyes.
The separation is not a metaphor for eclipse. Eclipses are not mentioned in the Kojiki or Nihon Shoki. The myth explains the permanent division of day and night, not a temporary covering.
FAQ
Why did Tsukuyomi kill Ukemochi? He was disgusted by the way she produced food from her mouth, nose, and anus. He considered it impure and killed her in anger.
Are Amaterasu and Tsukuyomi twins? They were born at the same time from Izanagi’s purification, but the texts do not call them twins. Amaterasu came from his left eye, Tsukuyomi from his right eye.
Does Tsukuyomi have any children? The Nihon Shoki mentions a son, but the lineage is inconsistent. Tsukuyomi is not a major progenitor in Shinto genealogy.
Why is Tsukuyomi less worshipped than Amaterasu? Amaterasu is the direct ancestor of the Japanese imperial family and the central deity of the state. Tsukuyomi’s role is secondary, and his estrangement makes him a less accessible figure for public worship.
The schism between Amaterasu and Tsukuyomi is not a myth of celestial mechanics. It is a story about boundaries, disgust, and the consequences of breaking trust. The sun and moon remain separated by a choice that cannot be unmade. For more on the divine feminine in Shinto, see our guide to Amaterasu and the Sun Goddesses. Explore the symbolism of sun and moon in world mythology. And for a deeper look at Shinto cosmology, read our guide to the Kojiki creation myths.