In Dictionary, it is said that Definition of Meditation is as follows.

A. a) The act or process of Meditating
    b) A devotional exercise or leading to contemplation.
B. A contemplative discourse, usually on a Religious or philosophical subject.

Kock Sun-Do is used in Meditation Retreat, This is a kind of physical exercise leading to meditation, and has been used from the beginning of Korean History. There are many members, including government offices, universities, and companies, training this Kock Sun-Do.
You may know and experience this exercise through Meditation retreat

Kouk Sun-Do is the Korean traditional method of training the mind and body which has descended from the Korean founding fathers about 9,700 years ago. It is the secret of preserving one's health, remaining free from disease, in good health, and in full vigor.
Our good old ancestors, having learned this method, taught it to the general public. Kouk Sun-Do flourished in the Three Kingdoms Era (around A.D. 300 - A.D. 700). However, Kouk Sun-Do was forced to leave the public and go into the mountains due to political persecution during the Chosun Dynasty and Japanese ruling periods. Thus, Kouk Sun-Do descended secretly in the mountains until Master Chungsan revealed again it to the public in 1967.
At the age of twelve, Chungsan met Master Chungwoon at the Tae Hahk Mountain in a strange twist of fate and received lessons in Kouk Sun-Do from the Master for more than 20 years. Mastering Kouk Sun-Do, he left the mountain in 1967 and started to spread it to the public. He wanted people all over the world, regardless of religion, race, and nationality, to be healthy and enjoy a better quality of life through the Kouk Sun-Do practice. In April, 1970, he opened the Kouk Sun-Do Training Center in Seoul, Korea. Since then, a great number of people, including people of various nationalities as well as Koreans, have practiced it, and have enjoyed a better life.
The practice of Kouk Sun-Do involves lower abdominal breathing along with special postures. The breathing practice improves and revitalizes the autonomic nervous system and self-healing and restoring forces of our body. Hence, all diseases disappear spontaneously. Continuous lifetime training results in genuine health of both body and mind.
The major advantage of Kouk Sun-Do over other practices is that it is the safest way. This is because Kouk Sun-Do has a scientific training system. Kouk Sun-Do has three practicing stages: the Chung Gahk Do stage, the Tong Ki Bup stage, and the Sun Do Bup stage. In the Chung Gahk Do stage, we mainly focus on body training (of course we do the simultaneous training of body and mind). In the Tong Ki Bup stage, we concentrate on spiritual training. In the Sun Do Bup stage, we practice to unify mind and body completely with the universe.
Without having a complete and healthy body, it is hard to reach a high level of spiritual training. Because lifestyles today are very complicated and lead to the weak body condition, it is not desirable to consider the body as the shadow of the mind and regard only the spiritual practice as of great importance. It thus may be harmful to train just the mind or to suppress the body desire through
fasting and penance. Practices, which use the brief and simple methods of expelling the impure fumes (toxins and wastes) of the body and then directly enter the spiritual practice, are not appropriate to us today with our weakened body conditions from living in our complicated society.
Since we practice first the Chung Gahk Do stage in Kouk Sun-Do, which mainly focuses on body training, and then enter the Tong Ki Bup stage, in which we train the spirit intensively, Kouk Sun-Do is the safest and most appropriate method for us today. Moreover, Kouk Sun-Do has nothing to do with religion. It does not promote any religious position or faith. Therefore, regardless of religion or faith, anyone can practice Kouk Sun-Do.

Literally, Kouk Sun-Do means the way (Do) of nature that man and heaven (Sun) communicate each other within the universe (Kouk). In ancient Korean, Kouk Sun-Do is called "Park Dol Bup." "Park" means sun, brightness, and heaven. Our ancestors were in awe of and respected Park as an entity with the tremendous power which shows all living things infinite favor.
"Dol" is a verb that means 'turn round and round' and "come round," and represents the yin-yang movement of Ki. It is the word expressing that all things return to the substance of the universe: they are created, become old, and seemingly disappear by changing form and circulating further within the universe. These are the laws of nature and the universe - the laws of creation and evolution.
Therefore, Park Dol Bup (Kouk Sun-Do) can be defined as the practice of a method to respect Park, the source of being and life, and to receive its tremendous power into the mind and body. This is the method, with cultivation of the body and mind, to awaken the law of creation and evolution and to properly participate in the law of the universe. Kouk Sun-Do's objective, thus, is not only to preserve health, but also to cultivate the whole man with the absolute physical-strength, the ultimatemental-power, and the supreme noble-mind.

The purpose of Kouk Sun-Do's breathing is to consolidate the physical and physiological breathing with the mind and to link this process into the unified, transformative movement of yin and yang - the dynamic process of opposites from which all life springs.
The One-Ki-Element theory and the Yin-Yang theory in oriental philosophy name the basic substance of the universe as "Ki." There are three different kinds of Ki: Chun Ki (the energy of the heaven, of the stars), Chi Ki (the energy of the earth), and In Ki (the energy of self, of nature). One Ki exists metaphysically in the polarity of yin and yang. It denies the dualistic thought that material and spirit are separated. It is opposed to the material concept found in western science, instead embracing the oriental concept with its belief in the duality and interdependence of the material and the spiritual world. All things in the universe are created by transformations in this one Ki. The appearance of the creation comes out in the form of five primary elements: water, fire, wood, metal and earth. The human organism is also created by the yin-yang and five-primary-elements movements of Ki. The five vital organs and six viscera are established and transformed by the Ki. The road of energy (Ki) movement in the human body is called "Kyung (latitude) - Rahk (longitude)." The point where "Kyung" and "Rahk" cross is named "Hyul." Both the yin-yang and the five primary elements are considered as the variations of one Ki. Thus, all things are created by the yin-yang and five-primary-elements movements of Ki.
By drawing the Chun Ki (which comes into one through the air) and the Chi Ki (which is acquired through foods and water) into the lower Danchun and then generating the yin-yang movement of these two Kis, Kouk Sun-Do's breathing creates the "Won Ki," the basic energy, which is one of the most crucial form of energy for our overall health. When we have sufficient energy in the lower Danchun we generally feel balanced and centered. When we have insufficient energy we feel a general physical weakness and imbalance.
Man is a part of the Great Universe, but he is also an independent small cosmos with self-consciousness because man has a spiritual function other than that of the universe. Therefore, it is important to consolidate the physiological energy of man into both the Chun Ki and the Chi Ki. The principle of Kouk Sun-Do is to cultivate the body and mind, to awake the law of creation and evolution, and to properly participate in the law of the universe. Thus, Kouk Sun-Do's breathing methods have a powerful influence on the quantity and quality of physical, mental, and spiritual energies, and thus on the organism of the body, our health, and our life. Through Kouk Sun-Do's breathing practice,
we not only keep our lower Danchun filled with energy, but we also achieve absolute physical-strength, the ultimate mental-power, and supreme noble-mind.

There are three stages in Kouk Sun-Do practice. The first stage is Chung Gahk Do, which is organized into three levels: Choong-Ki Danbup, Kun-Gon Danbup, and Won-Ki Danbup. The second stage is Tong Ki Bup, which is also organized into three levels: Chin-Ki Danbup, Sam-Hap Danbup, and Cho-Ri Danbup. The final stage is Sun Do Bup, which is composed of Sam-Chung Danbup, Mu-Chin Danbup, and Chin-Gong Danbup.
In practising Chung Gahk Do, we start with doing the method of circulating and distributing Ki (Ki-Hyul Sunwhan Yutong Bup) as a warm-up. Following the warm-up exercise, we do the main exercise. In the main exercise, we train with the Danchun breathing along with special postures and meditation (Danchun Haengong). There are 50 postures in Choong-Ki Danbup, 23 postures in Kun-Gon Danbup, and 360 postures in Won-Ki Danbup. After the main exercise, we finish with a concluding exercise, which makes the Ki (energy), conserved through the Danchun breathing, flow throughout our body, and Ki-Shin Bup, which strengthens the inner organs of our body.
Practising Chung Kahk Do increases 'Won Ki' (the basic energy), keeps your Danchun filled with this energy, and circulates the energy into every "Kyung-Rahk". This process makes you feel fresh of mind and strong of body. The inharmony of both body and mind spontaneously disappear, you feel real health, and the gates of wisdom open allowing you to look at world affairs clearly and honestly. Also, you feel strength flowing to the hands and feet, you have the greater powers of endurance, and you sleep better. The hands and feet become warmer, and you feel warm energy circulating in the hands and feet. When you climb a mountain, you are not out of breath and you feel the continued growing of strength. Your skin becomes more elastic and your weight returns to normal. You feel new strength, have a bright and peaceful mind, and become broad-minded and generous.
After finishing the Chung Kahk Do stage, you begin the practice of Tong Ki Bup. In this stage heaven and man are truly in harmony, and you will feel the real sense of the practice. After the Ton Ki Bup stage, you begin the Sun Do Bup stage, the last stage of Kouk Sun-Do, which brings you into ultimate
harmony with the universe. The road through the practice of Kouk Sun-Do is endless. Kouk Sun-Do is a complete and perfect system and has the longest history of any other way. Its real effects are boundless and you can feel them only through the practice of Kouk Sun-Do.

"Use nose for breathing, inhale and exhale slowly and calmly, and make movement quietly. Breath with postures, but breath gently."
The meaning of "use nose for breathing" is to inhale and exhale through the nose in a natural manner as in everyday life. However, for those just starting the breathing practice, those who are filled with toxins, the mouth can be used in exhalation for two or three days. Even for those in the main practice, whose stomachs are enervated and filled with toxins from the intemperate eating styles, and who have many thoughts and agonies due to the hardships of life, the mouth can be used in exhalation for several respirations before returning to normal breathing. In addition, sometimes the mouth can be used, if needed, in practicing an external exercise or in circulating Ki.
The "inhale and exhale slowly and calmly" means to breathe in tenderly, uniformly, deeply, and for a long duration during inhalation, and to breath out softly, gradually, and quietly during exhalation. The meaning of "make movements quietly" is to move without distracting the concentration of the mind, to watch or sense the flow of Ki depending on the movement being made. Making movements (Haeng Kong) helps to solve the discord among bones, skin, and muscles, to refine the flow of Ki, and to link the practice to everyday life. The "breath with posture, but breath gently" means that all postures have to be done while breathing, that breathing should not be stopped abruptly and should be done without any sound. It is unnatural to breath chokingly, with shortness of breath, or alternating between discrete and continuous intervals.
Some people move slowly like a tortoise, with the belief that fast movements of the body found in everyday life through, for example, exercises and sports, disperse the energy (Ki) acquired from the breathing practice. Slow movements may help breathing practice or mind training with loading the consciousness, but as long as balance with centering around the Danchun is not lost, the appropriate exercises smooth the circulation of energy and blood, make the spirit clear, and help to store ki. In the practice of Chin-Ki Danbup, of course, we should move more carefully than a tortoise and be prudent in our conduct. However, in the Chung Gahk Do stage, since the labor and sports in our life help us store Ki, we need not worry about them. It is important to use the body impartially, caring about the balanced development of muscles and the smoothing circulation of energy and blood.
Moreover, sages of old teach us to raise the spiritual force with minimal thoughts, to raise internal energy with minimal words, and to raise the physical energy with minimal food. Today especially we must keep this teaching in mind and practice it diligently. Also, practitioners today need to exercise diligently and to control all desires, reminiscent of the spiritual life of our old ancestors.