The way of meditation has changed significantly since the opening of the Sahasrara chakra, and a state of purity is maintained (basically) by simply remaining as it is. Occasionally, a cloud of aura or a cloud of emotions and memories appears unexpectedly, but immediately that cloud is enveloped in light and disappears into a transparent space.

For a moment, a memory comes up, and a certain percentage of the body is enveloped in a cloud-like aura. As the memory resurfaces, the emotions from that time also resurface slightly, but immediately, it is enveloped in a light-like aura and disappears into a transparent space (which is also light). It lasts for about 3 seconds at most, and up to 10 seconds at longest. If it were a long time ago, it might be a trauma lasting 30 seconds or several minutes, or if you think about it at that time, it might be a trauma that caused you to worry for days or weeks. However, even when that memory resurfaces, it simply remains as it is, and the aura of that memory naturally disappears into the light.

It seems that some schools of thought describe this as a state of natural self-liberation. I haven't specifically studied that school of thought, but as far as I can tell from reading books, it is very similar to the "landrul" state in Dzogchen, which means "naturally liberating oneself."

It is said to be like a fire spreading in a forest. The subjective feeling naturally calms down, and the practitioner experiences primordial wisdom. As soon as an object arises, it is recognized as being empty, just like one's own state of emptiness. "Rainbows and Crystals" (by Namkai Norbu).

If read literally, this could be interpreted as "recognizing that it is empty (in relation to concrete objects)," and I used to interpret it that way. However, it seems that it is not that, but rather that even when a concrete concept arises as a contrast (what Buddhism calls color, form, or rūpa), it immediately and automatically disappears and dissolves into emptiness, thereby directly recognizing the transformation. It seems that it is about vividly seeing in one's mind that the concept of a concrete object (which is called color in Buddhism) is the same as emptiness.