In yoga, Kechari Mudra is one of the techniques that was traditionally considered a secret teaching, but in recent times, it has become quite an open secret. The method is something you should research on your own, but there are several variations, and basically, it involves maintaining a state where the tip of the tongue is raised. When being taught, it is often said, "Do as much as you can." Also, although it may not be strictly Kechari Mudra, some schools teach that it is sufficient to simply place the tongue against the back of the upper teeth. The basic principle is "to raise the tongue," and while it is generally considered that raising it as high as possible is ideal, some schools teach that it is not necessary to raise it that high, and that "as much as possible" is sufficient. Some Shiva-related schools strongly recommend raising the tongue significantly, and there are even extreme schools that cut the underside of the tongue with a razor to make it easier to raise. The Hatha Yoga Pradipika and Shiva Samhita describe these traditional methods. However, most schools do not go to such extremes, and simply focus on raising the tongue. In traditional settings, there are often cases where people are hesitant to even mention that they are practicing Kechari Mudra, due to its extreme nature. Although it has become well-known recently, it was traditionally a secret teaching. However, nowadays, when people talk about Kechari Mudra, it usually means simply maintaining the tongue in a raised position as much as possible.

In meditation, the position of the tongue is sometimes specified by the school, but nowadays, in most cases, there are no specific instructions regarding the tongue. Even in schools where Kechari Mudra is taught as important, it may not be properly taught until a certain level of practice is achieved. Therefore, people often decide whether or not to practice Kechari Mudra based on their own judgment, but many people do not know the correct method.

As a lighter approach, (although it may not be strictly called Kechari Mudra), placing the tongue against the back of the upper front teeth can help reduce distractions during meditation. This may be worth trying for those who meditate, but it may not be suitable for everyone. In my case, I have sometimes done this, but basically, I have kept my tongue in a natural position and have not practiced Kechari Mudra. However, recently, I tried practicing Kechari Mudra properly, raising the tongue as high as possible, and surprisingly, it had a tremendous effect. The basic method of Kechari Mudra is to raise the tongue, but there are slight variations in the methods depending on the school.

As a fundamental premise, various yoga techniques should not be imitated blindly; they require proper instruction from a qualified teacher. Based on this premise, imitating techniques seen in books or videos is not recommended. There are often incorrect methods, and a teacher is needed to quickly correct any negative consequences. However, I understand that many people still imitate techniques from videos, and while I don't recommend it, perhaps it's acceptable to proceed with caution and at one's own risk.

Recently, I've personally realized that while I didn't feel much effect from Kechari Mudra before, since the Sahasrara chakra has opened slightly, Kechari Mudra seems to have a significant effect on opening the Sahasrara.

The degree of opening of the Sahasrara varies depending on the day and one's overall condition. Even on days when the opening is not good, simply sitting in meditation and opening it can be effective. However, there are also days when it doesn't open easily. In such cases, performing Kechari Mudra and extending the tongue upwards, even without applying force to the tongue, can be effective. However, when the opening is particularly poor, applying slight pressure with the tongue on the upper part of the mouth can transmit that pressure to the forehead, causing the skull to make a slight "piki-piki" sound. This pressure, in addition to the physical pressure, seems to change the direction of the energy flow, making it easier for the Sahasrara to open. In reality, it's not directly upwards, but slightly forward, and the tongue doesn't easily reach straight up, so it tends to stick to the upper part of the mouth. Therefore, it's about applying pressure in a direction that is easy to push, in a slightly slanted direction.

Meditation is often thought of as purely a mental practice, but when it comes to the Sahasrara, the degree of opening seems to be proportional to the relaxation of the skull. When the Sahasrara is not open, the skull is stiff, and as meditation progresses, the skull gradually makes a "piki-piki" sound and gradually relaxes, and the Sahasrara opens accordingly. Therefore, you can relax the skull by focusing on the forehead or the top of the head (Sahasrara) during meditation. However, applying pressure with the tongue from the mouth in Kechari Mudra can achieve the same effect, relaxing the skull and making it easier for the Sahasrara to open. Yoga exercises, such as inversions like headstands, can also relax the skull, but they are difficult to do frequently or for long periods. In that sense, Kechari Mudra is relatively easy and effective. If the Sahasrara is already relatively open, simply changing the direction of the tongue or focusing with awareness can be sufficient to open it further. However, if it's difficult to open, applying physical force with the tongue may be helpful.

It seems that until this stage, I couldn't feel much effect, which means that even though there is an effect, the Sahasrara chakra might not have been ready to open. It seems that the effect of Kechari Mudra alone is not that strong. However, if the skull is loosened to a certain extent and the Sahasrara chakra is becoming easier to open, it seems that it can produce a tremendous effect. I have never felt such a tremendous effect before.

With this, it feels like energy is flowing not only to the Sahasrara chakra but also to the area between the eyebrows, and energy is gathering near the top of the head.

Normally, the Sahasrara chakra is open, but depending on the day's condition, it sometimes seems like it is not open very much. In such cases, it can be opened very quickly with a little effort, so it might be useful as a trigger to open the Sahasrara chakra on days when the condition is not very good. It also seems to have the effect of completely opening it on days when it is only slightly open, but sometimes the effect is so strong that it can be overwhelming, so it tends to be unstable. If you have time, it might be better to use conscious effort over a longer period of time, but it might be a good way to use it as an initial push when it doesn't open easily, or to adjust it when it feels slightly unbalanced or not fully open. However, this is still in the stage of verification and observation.