According to the teachings of yoga, the ajna (third eye chakra in the forehead) and the muladhara (base chakra in the perineum) are directly connected, and any change that occurs in one will manifest in the other. Therefore, it is said that stimulating the ajna will cause a reaction in the muladhara, and stimulating the muladhara will cause a reaction in the ajna. Stimulation does not necessarily have to be physical; simply focusing one's consciousness can cause changes. This is why, in order to awaken these chakras, stimulation is given to the corresponding chakra. This is explained in detail in the works of Honzan Hiraoka.

The basic principle of meditation is to focus on the ajna in the forehead, which is said to be to awaken the ajna so that the disciple is not entangled in karma. The muladhara is also said to be the place where all karma sleeps, and there is a risk of being trapped by karma if the muladhara is stimulated before the ajna.

However, the awakening of the ajna that I am referring to here seems to have several stages, and as an initial stage, it is better to understand it not as a supernatural ajna, but as a way to activate consciousness and live a healthy life.

In this way, by focusing on the ajna, purification gradually progresses, and the karma sleeping in the muladhara is resolved one by one.

The ajna is also the third eye and has the role of seeing all things, but initially, this is not very important; as an initial stage, although it is simply said, it is an important role to prevent being entangled in karma.

As a reaction from the muladhara to the ajna, stimulating the muladhara by placing the heels against the perineum or slightly contracting and expanding the perineum during seated meditation can make it easier to awaken the ajna. It takes time for the effect to appear, but stimulating the muladhara is an effective method that can be used for a long time, from the early stages of practice to later. If there is little reaction when simply focusing on the ajna, stimulating the muladhara as described above can cause a reaction in the ajna. Initially, it may only cause a tingling sensation on the surface of the forehead, but in some cases, the reaction may be more pronounced and reach the inside.

The connection is said to be through the center of the body, and when the muladhara is stimulated, energy travels through the lower back, near the sushumna, and reaches the ajna in the head.

In books, it is described as mutual interaction, but personally, I feel that it is mostly a one-way flow from Muladhara to Ajna. There may be individual differences.