In Esoteric Buddhism, it is said to "embody the radiant light of the sun within the heart," and it is said to observe the light of the sun ideologically, or to contemplate "the morning star," likening it to the experience of Kobo Daishi. This originates from the union of Brahman (the cosmic self) and Atman (the individual self), as described in the Upanishads of India-Yoga or Vedanta. On the other hand, Shinto says that the higher spirits are spirits that shine like the sun, so Shinto's sun worship is to always worship the actual sun. ("Modern Interpretation of Shinto," p. 202)

Although different from Esoteric Buddhism, Yoga, and Shinto, it is interesting that they all have in common the point of "embracing something radiant within oneself."

I am not very familiar with Shinto meditation, but "Chin-kon Kishin" is often mentioned, and it seems to refer to this.

In Shinto, one meditates on the spirit that shines like the sun, welcoming the divine into one's own spirit. This is called "Chin-kon Kishin." Also, it is called "Mitamashizume," which means to be assimilated into the immeasurable "love, wisdom, courage, peace, joy, and tolerance" of the higher spirits that shine like the sun. (Same book, p. 203-204)

Shinto's "Fukon" seems to mean something similar. This is based on the Shinto concept of "unity of god and man," and in the past, people who were unified with higher spirits were regarded as the same as the higher spirits, and considered as a unification of humans and spirits. For example, Ohime, an ancestor of the Emperor, was considered the same as Amaterasu. According to the same book, the Indian sage Shankaracharya was said to have become one with a radiant spirit, and such examples are said to be frequent.

When comparing it to my own experiences, the first was the Higher Self that approached from behind the Anahata chakra in my chest and connected and became one about two years ago, and since then it has been attached and fused, but recently, a strong aura-like consciousness suddenly attached to the Sahasrara chakra on top of my head, passed through the axis of my body, through my throat, and entered the Anahata chakra. Although comparing it to an example like the Emperor may be an exaggeration, there are similarities.

Although both are similar to these kinds of stories, they are not completely the same, and in any case, what is important within my heart (in Shinto terms, it is a spirit), and (in Yoga or Vedanta terms, it is Atman), but anyway, something important has come down into my heart, and I always feel like I want to cherish it. Although the way of saying it is various, these kinds of stories and my recent experiences are similar, and they help me interpret my recent situation.

In Vedanta, the term "Atman" originally refers to a pure observer who does not act. In this case, the term "Atman" is somewhat inappropriate. However, in yoga scriptures, there are stories about "embracing Atman within the heart." The term "Atman" is difficult to understand literally, so it is more appropriate to use the term "Purusha" in a yogic sense. Purusha is pure consciousness, but it always exists together with Prakriti, which is material. They are not completely one, but have a difference, like individuality. When transcending Purusha, reaching the creator god or the true meaning of Atman, or Brahman, there is complete oneness. However, in the case of Purusha, there is still a difference. This is not about the ego, but about a difference in nature and existence itself. Astral and causal bodies are material, but Purusha is pure consciousness that transcends matter. Each Purusha has differences and individuality. Yoga and the Upanishads describe "embracing" these individual Purushas within the heart. This is similar to Esoteric Buddhism and Shinto.

Some texts use the term "Atman" here, but if it is expressed in that way, those who have already experienced it will immediately understand what it refers to. However, if it is expressed as "Atman" literally, it is a pure observer, and there is only one Atman, and there are no two Atmans. Therefore, "embracing the one Atman within the heart" is meaningless from the original meaning of the word "Atman." However, in this context, if "Atman" is used, it should be read as referring to an individual Purusha (divine spirit), setting aside the original meaning of "Atman."

These concepts are common to spirituality, but readers tend to read them in separate categories, so they may not realize that they are the same, or they may perceive them as completely different stories. However, these concepts seem to be common to spirituality.

Christianity speaks of the Trinity (some denominations claim that the Trinity is only possible for Christ), but according to the writings of Professor Honzan Yamaoka, "embracing Purusha within the heart" corresponds to the Christian Trinity.

When you look at it this way, it seems that the concept of union with Purusha (divine spirit) in yoga is common to various spiritual teachings in the East and West, both ancient and modern.