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Asian Medical Theory - Vital Substances
Origins and Approach   |   Yin and Yang   |   Five Elements  |   Vital Substances   |   Zang-Fu Organs

"The greatest mistake in the treatment of diseases is that there are physicians for the body and physicians for the soul, although the two cannot be separated." - Plato

Vital Substances

yin yang Of the many principles of traditional Asian medical theory, a few fundamental ones will be discussed. These are:
  • Yin and Yang Theory
  • Five Elements Theory
  • Vital Substances Theory
  • Zang-Fu Organ Theory
  • External Causes of Disease
  • Internal Causes of Disease

  • Asian medical philosophy views the body as a vortex of Qi and the interaction of the body's vital substances, rather than as a system of discrete organs, albeit there is a highly developed Organ-systems theory that interacts within the philosophy. There are two meanings to 'Qi'. One meaning describes it as 'vapor', 'steam' or 'gas'. The second meaning describes it as 'uncooked rice'. The two meanings indicate that Qi can be as rarefied and immaterial as air or as dense and material as uncooked rice grains. This exemplifies the view that Qi is manifested in many forms along a continuum.

    Many possible translations of 'Qi' have been proposed. The popular translations are 'energy' or 'vital force' or 'material force' and so forth, consistent with modern physicists' view of Qi as a continuum of matter and energy. Various studies on the nature of Qi have proposed many theories including the possibility that Qi may be 'radioactive emanations' or protein elements.

    Whatever Qi is and however it is translated, Qi is at the basis of all matter and phenomenon in the universe. And all the various manifestations of matter and phenomenon are the result of the continuous coming together and dispersion of Qi including life, death and all things in-between.

    Of the many characteristics of Qi that exists, two are especially important to medicine:

    • Qi is in a constant state of change in varying states of aggregration and dispersion.
      • When Qi aggregates (condenses) energy is transformed and takes on physical form. 
      • When Qi is dispersed more subtle forms of matter are formed. 
    • Qi manifests simultaneously on the physical, mental, and spiritual levels.

    'Qi' as a term is used in two ways:
    1. Qi as a refined substance and energy produced by the Internal Organs and manifesting as the various types of Qi, depending on their location and function. These include Defensive (Wei) Qi which circulates on the 'exterior' between the skin and muscles to warm and protect the body, Nutritive (Ying) Qi which circulates in the blood and organs to provide nourishment, Food (Gu) Qi which is the first stage of transformation of food into Qi, True (Zhen) Qi which is the final stage in transformation of food and air to produce Qi, and so on.
    2. Qi as functional activity of the internal organs rather than as a refined substance. For example when we refer to Lung Qi it is not the Qi residing in the lungs but to the complex of the lung's functional activities which are inhaling air and descending Qi to the internal organs. This is what is referred to when we speak of Lung Qi, Heart Qi, Liver Qi, Stomach Qi, Kidney Qi, etc.
    There are many different types and manifestations of Qi each representing varying degrees of aggregation or dispersion, and each carrying on different functions. Among these, five Qi types are called the Vital Substances. They are vital because they are essential for life.

    The five Vital Substances are:
    • Essence
    • Qi
    • Blood
    • Body Fluids
    • Mind (Shen)

    Essence (Jing)

    "Pre-Heaven Essence originates from the parents,
    the Post-Heaven Essence originates from food."

    (Golden Mirror Medical Collection)

    Essence (Jing) is a form of Qi that is refined, distilled and extracted from a coarser substance. Because of the time expended, and the multilayered processes involved in refining and distilling a substance in general, such substances can be considered rare and precious. Likewise, Essence is limited in quantity and is therefore something to be guarded and protected.

    There are three kinds of Essence:

    1. Pre-Heaven Essence
    Also called Pre-Natal Essence, Pre-Heaven Essence can be considered the composite of the genetic materials contributed to the embryo by the father's Yang Essence (Sperm) and mother's Yin Essence (Ovum). This Essence is formed at conception and develops during fetal development. During the pregnancy this Essence nourishes the fetus and relies on the nourishment provided by the mother's Kidneys. While in the womb Pre-Heaven Essence is the only kind of Essence present in the fetus.

    Pre-Heaven Essence is what determines our constitutional makeup, strength and vitality. It may be considered our genetic blueprint.

    The Yang aspect of Pre-Heaven Essence is said to reside in a theoretical place between the Kidneys called the Fire of the Gate of Life (Ming Men). The Ming Men provides the Physiological Fire to warm the body and carry on its physiological processes.

    The Yin aspect of Pre-Heaven Essence becomes the Kidney Essence proper. It is this Kidney Essence proper which resides in the Kidneys and matures at puberty producing Sperm in boys and the Ova and menstrual blood in girls.

    As we age there is a gradual decline in both the quantity and quality of Pre-Heaven Essence. Because it is inherited from our parents and considered to be fixed it can be influenced only with great difficulty, if at all. Some believe its quantity and quality are fixed and cannot be replenished. Others believe that due to its interaction with Post-Heaven Essence, its quality may be positively influenced through balance. These include healthy lifestyle, proper diet and moderation of all things including work, sexual activities and exercises that promote deep breathing such as Tai chi and Qi gong.

    2. Post-Heaven Essence
    Also called Post-Natal Essence, Post-Heaven Essence is derived from the foods and fluids processed, refined and extracted by the Spleen-Stomach system. This Essence nourishes the newborn only after it has left the mother's womb and is influenced continuously throughout one's life. In a sense this not a specific type of Essence but a general term to indicate the essences produced by the Spleen-Stomach system from processing foods and fluids.

    3. Kidney Essence
    Kidney Essence is derived from both Pre-Heaven and Post-Heaven Essences and has an extremely important role in human physiology. The Pre-Heaven aspect of Kidney Essence gives it a hereditary energy and this determines our constitution. While Pre-Heaven Essence cannot be replenished, this Kidney Essence interacts with Post-Heaven Essence so it can be replenished over a long period of time.

    The functions of Kidney Essence are:

    a. Growth, Development and Reproduction:
    Kidney Essence is the organic substance which governs and controls human growth, development, sexual maturation, reproduction, menopause and aging. Ancient texts say that men's Essence flows in 8-year cycles and women's Essence in 7-year cycles. This is one basis for girls maturing faster than boys. Aging reflects the decline of Kidney Essence.

    b. Basis of Kidney-Qi
    Kidney Essence is fluid-like and can be considered an aspect of Kidney Yin. Kidney Yang, on the other hand, is the energetic in form and provides the fire to Kidney Yin (water-like) to form the Kidney Qi (vapor-like). Kidney Qi provides the energy to help various organs carry on their functions including grasping of Lung Qi to promote breathing. An inability to grasp Lung Qi may lead to asthma. It also provides Qi to the Bladder to help its function of processing fluids and excreting urine.

    c. Basis of Constitutional Strength
    Kidney Essence determines our basic constitutional strength. This includes our immune system and its ability to protect the body from exterior contracted pathogenic factors such as colds, flu and infections. The immune system functions are best described as Defensive Qi (Wei Qi). Defensive Qi has the function of protecting the body's exterior but it draws its roots and strength from Kidney Essence. Many childhood disorders including allergy, eczema and developmental problems may result from a deficiency of Kidney Essence.

    d. Basis for the Three Treasures
    Essence (Jing), Qi, and Mind (Shen) are called the 'Three Treasures'. Essence and Qi are the material and essential foundations of the Mind. These three represent different states of condensation of Qi. Essence is dense and represents Earth in the Cosmologic Sequence. Qi is more rarefied and represents the Human. Shen is the most subtle and immaterial form and represents Heaven. This Triad provides the interrelationship of the Mind-Body-Spirit connection. A healthy mind depends on the strength of Pre-Heaven Essence stored in the Kidneys, and Post-Heaven Essence produced by the Spleen-Stomach system. Together, Essence, Qi and Mind are the fundamental physical and mental-spiritual bases of human beings.


    Forms of Qi
    Qi is manifested in many forms depending on their location and function. There are over 20 different forms of Qi in the body. A few of the more significant forms are discussed below.

    1. Original Qi (Yuan Qi)
    Also known as 'Yuan Qi', it is Essence transformed and manifested as Qi. Original Qi is the foundation of all the Yin and Yang energies of the body and has the following functions:

    a. Motive Force
    Original Qi is, like Essence, the foundation of vitality and constitution. But as a form of Qi it circulates all over the body through the acupuncture energy channels and provides the force for the functional activities of all the organs. It serves as the link between Essence and Qi.

    b. Basis of Kidney Qi
    Original Qi is the basis for Kidney Qi and is closely involved in the Kidney's functions. It resides between the Kidneys at the Gate of Life (Ming Men) and helps provide the heat to carry on the body's physiological activities.

    c. Helps Transform Qi
    Original Qi is like a catalyst that helps earlier forms of Qi to the final stage of transformation into Qi proper.

    d. Helps Transform Blood
    Original Qi helps transform Food Qi into Blood in the heart.

    2. Food Qi
    Food Qi is the first stage of transformation of food into Qi in the Spleen-Stomach system. It is extracted from food by the Stomach and sent upwards by the Spleen for further transformation. Food Qi is also the basis for production of Qi and Blood. Ancient sources say: "If no food is eaten for half a day, Qi is weakened. If no food is eaten for a whole day, Qi is depleted." Similarly in Western medicine, it is noted that the body begins to tap into lean muscle mass as a source of energy within 12-18 hours of fasting.

    3. Nutritive Qi (Ying Qi)
    Nutritive Qi is related to Blood and flows with it in the blood vessels and channels to nourish the internal organs and the entire body. It is said that this is the Qi that is activated when needling an acupuncture point. Its importance is related to its function of regulating the 5 Yin organs (Liver, Heart, Spleen, Lungs and Kidneys) while moistening the 6 Yang organs (Gallbladder, Small Intestines, Stomach, Large Intestine, San Jiao and Urinary Bladder)

    4. Defensive Qi (Wei Qi)
    Nutritive Qi flows in the interior to nourish and warm the interior. Defensive Qi flows on the exterior (outside the channels) between the skin and muscles. Its function is to protect the body from exterior pathogenic factors such bacterial and viral infections; to warm the muscles; and to open and close the pores of the skin. Defensive Qi is controlled by the Lungs so that a weak Lung Qi may lead to a weak Defensive Qi making one prone to frequent colds and spontaneous sweating from chronically opened pores.

    Although Defensive Qi flows on the exterior (between skin and muscles) and is responsible for protecting the exterior while the Nutritive Qi nourishes the interior, Defensive Qi also affects the interior as well. This is because in the evening, Defensive Qi flows inward to warm the Yin organs: first to the Kidneys, then Heart, Lung, Liver and Spleen (corresponding with the 5-Elements Controlling Sequence). In a 24-hour period Defensive Qi circulates throughout the body 50 times: 25 times on the exterior during the day, and 25 times in the interior during the night.

    5. Upright Qi (Zheng Qi) vs Pathogenic Qi (Xie Qi)
    Upright Qi is not a different type of Qi but is a term to represent the collective functions of the many types of Qi in their protection of the body. It is given meaning when used in relation to pathogenic factors. Pathogenic factors are collectively referred to as Pathogenic Qi (Xie Qi) when used in relation to the body's collective strengths to fight it (Upright Qi).

    Functions of Qi
    Irrespective of the various types of Qi that exist, all Qi of the body have at least six general functions. They are:

    1. Transforming
    Qi is Yang in nature. This means that Qi is the moving and functioning aspect of all things. Within the body, dense and material forms of matter such as food must be transformed into their usable forms. The Qi of the various organs are involved in the transformation of various substances. Some examples are: Stomach Qi 'rots and ripens' foods and passes it on to the Spleen Qi which transforms it into Food-Qi; Kidney Qi transforms fluids of the body to usable Yin; and Bladder Qi transforms impure fluids into urine, etc.

    2. Transporting
    Together with the function of transforming various substances, Qi transports them into and out of body structures including tissues, muscles and organs. Some examples of transportation of Qi are: Liver Qi transports Qi in all directions; Lung Qi transports Qi downward and also transports fluids to the skin; Spleen Qi transports Food-Qi, etc.

    3. Holding
    Qi also has the function of holding various substances in their proper receptacles. For example: Lung Qi holds sweat by controlling the opening and closing of the pores; Spleen Qi holds Blood in the blood vessels; Kidney and Bladder Qi's hold urine, etc.

    4. Raising
    As part of its holding function, Qi also lifts and keeps substances and structures in their proper place. For example, Spleen Qi lifts and raises organs in general and Kidney Qi raises the Uterus.

    5. Protecting
    While the Defensive Qi is primarily responsible for protecting the body from exterior pathogenic factors, all of the other forms of Qi working in harmony contribute to one's overall resistance to disease.

    6. Warming
    All the physiological processes of the body require 'warmth' to carry on their functions. The Yin substances of the body need warming energy (Yang Qi) to transform the raw substances into usable Qi forms, and then to transport them. The source of all Yang Qi of the organs resides in the Kidney Yang and the Ming Men.

    Directions of Qi
    Each type of Qi is associated with a specific direction of movement. It is the delicate interaction between Yin and Yang and among the Internal Organs, together with proper Qi flow that supports the complex balance of health and wellness.

    Examples of the directional movement of Qi are:
    • Liver Qi: ascends and distributes outward in all directions
    • Heart Qi: descends to meet with Kidney Qi
    • Spleen Qi: ascends
    • Lung Qi: descends towards Kidneys; ascends to distribute Defensive Qi and sweat over the skin
    • Kidney Qi: ascends to the Lungs; descends to the Bladder

    Pathology of Qi

    If the proper functioning of the various forms of Qi becomes disordered, pathology may develop. As it relates to Qi specifically, there are four distinct ways that pathology of Qi occurs. They are:

    1. Deficiency of Qi
    If Qi is not properly nurtured and nourished, it can become weak and deficient. Some factors that cause Qi Deficiency include improper nutrition, overwork, excess sexual activity, etc.

    2. Sinking of Qi
    This mostly applies to Spleen Qi and Kidney Qi where the Qi of these two organ systems become deficient. Sinking of Qi is generally a more chronic and more deficient form of Qi Deficiency. Symptoms and signs usually involve organ prolapse.

    3. Stagnation of Qi
    Any number of things can obstruct the proper flow of Qi causing it to stagnate in certain areas of the body. When Qi does not move, other substances including Blood and Body Fluids also do not move causing a variety of disorders including emotional imbalance, pain, menstrual irregularities, etc.

    4. Rebellious Qi
    Rebellious Qi indicates that Qi is not flowing in the proper direction. As indicated above, each Internal Organ has a physiological direction of Qi flow. When Qi is counterflowing the following pathologies may be seen:

    Liver Qi Rebellion:
    • Liver attacks its neighbors (Spleen and Stomach system) to cause digestive problems, acid regurgitation, belching, hiccups, etc.
    Heart Qi Rebellion:
    • Heart Qi fails to descend Fire to meet the Kidney Water. Without the cooling of Water, Heart Fire ravages and floats upward causing mental-emotional disturbance and irritability.
    Spleen Qi Rebellion:
    • Sp fails to ascend Food-Qi causing diarrhea.
    Lung Qi Rebellion:
    • Lungs fail to descend Qi to the Kidneys which aids in grasping the Qi. In this case Lung Qi rebels upwards causing coughing, sneezing, asthma, etc.
    Kidney Qi Rebellion:
    • Kidneys fail to send clear Qi to the Lungs, again leading to asthma and other respiratory disorders.
    • Kidney Qi may also fail to descend to the Bladder causing retention of urine.


    In traditional Asian medicine, Blood is a dense and material form of Qi. Blood and Qi are inseparable: Qi fills 'life' into Blood to give it movement, and Blood nourishes Qi. If Qi is Stagnant or Deficient, Blood will be Stagnant (non-moving). Therefore, Asian medicine's meaning of Blood as a dynamically moving substance is different from the Western meaning of blood as an inert fluid.

    Functions of Blood
    The main functions of Blood are:

    1. Nourishing
    • Blood flows with Nutritive Qi in the blood vessels and channels to nourish the internal organs and the entire body.  

    2. Moistening
    • Blood moistens all the tissue of the body.
    • Blood residing in different Internal Organs moisten different areas of the body. For example, Liver Blood moistens the sinews to keep them flexible and healthy. Liver Blood also moistens the Eyes, its related Sensory Organ. On the other hand, Heart Blood moistens the Tongue, its Sensory Organ, to ensure movement and speech.
    3. Provides the Material Foundation for the Mind
    • Blood provides the material foundation for the Mind (Shen).
    • Blood, being dense and fluid-like houses the Mind and anchors it. If Blood is deficient, the Mind will lack a foundation. This lack of foundation is manifested in a sense of unhappiness, uneasiness, vague anxiety and mild irritability.
    • If Deficient Blood cannot anchor the Mind at night, the Mind will 'float' while the person is sleeping to cause excessive dreaming or difficulty in sleeping.

    Relationship of Blood to Internal Organs

    Each of the five Yin Organs have a relationship with Blood as follows:

    • Heart governs Blood and the Blood Vessels which circulate it.
    • Heart is where Blood is made with the help of Food-Qi from the Spleen and Kidney Essence.
    • Spleen originates Blood because the Spleen produces Food Qi which is sent to the Lungs and forwarded to the Heart.
    • Spleen also holds Blood in the Blood Vessels.
    • Liver stores Blood. When a person is lying down, Blood flows to the Liver for storage.
    • Liver regenerates Blood. When Blood flows back to the Liver at night, Blood gets regenerated.
    • Liver Blood moistens the Eyes and Sinews.
    • Liver Blood supplies Menstrual Blood for a healthy menstrual cycle.
    • Lungs receive Food-Qi sent from the Spleen and send it to the Heart where it is transformed into Blood.
    • While the Heart governs Blood Vessels, the Lungs control all the Channels and Blood Vessels. It is the Lungs that provide the Qi to the Blood Vessels to help the Heart move the Blood.
    • In the Heart, the Original (Yuan) Qi of the Kidneys help transform Food Qi to Blood.
    • Kidney Essence can be transformed into Blood.

    Pathology of Blood
    There are 3 main pathologies of Blood as follows:

    Blood Deficiency
    • General Blood Deficiency can result from Qi Deficiency because it is Qi that makes Blood.
    • Blood Deficiency can manifest as mental anxiety, poor memory, numbness or tingling, scanty periods or amenorrhea, etc.
    Blood Stagnation/Stasis
    • Blood can become sluggish and fail to move properly. This is often due to Qi Stagnation mostly of the Liver, or by Heat, or by Cold.
    • Blood Stagnation/Stasis often manifests as a fixed stabbing pain and/or formation of masses such as tumors, etc.
    Blood Heat
    • Blood can become hot from a number of reasons such as an invasion of a Heat pathogenic factor, or Heat in an organ, especially Liver Heat.
    • Heat in the Blood can manifest as feverishness, skin eruptions, bleeding, etc.

    Body Fluids

    In traditional Asian medicine, two types of Body Fluids are recognized and are referred to as 'Jin-Ye'.

    'Jin' refers to the clear, light and watery substances like sweat. Jin circulates on the exterior skin and muscle layers to moisten and nourish the skin and muscles. It circulates with the Defensive (Wei) Qi on the Exterior.

    'Ye' refers to a denser, heavy and turbid fluid like synovial fluid, plasma and mucus. Ye circulates in the Interior - in and between the joints, tissues and organs. Ye fluids moisten and nourish the joints, spine, brain, bone marrow and the Sensory Organs such as eyes, ears, nose and mouth. It circulates with the Nutritive (Ying) Qi in the Interior.

    Source of Body Fluids

    Foods and drinks are the origins of the Body Fluids. Various organs are involved at each level to filtrate and separate the pure from impure parts.  This process can be summarized as follows:
    • This process begins when the Stomach receives foods and drinks. 
    • The Stomach undergoes a process of 'ripening and rotting' of foods and then sends it to the Spleen. 
    • Spleen-Qi then transforms and separates the 'clear' usable 'essence' of foods from the turbid parts. 
      • The Spleen sends the clear fluids to the Lungs which spread some of it over the skin to nourish and moisten the skin, and also send some fluids down to the Kidneys. 
      • The Spleen sends the turbid portion down to the Small Intestines for further separating into pure and impure fluids before passing the pure fluids to the Bladder and the impure fluids to the Large Intestines. 
    • The Bladder further transforms and filters the fluid into an even more pure and impure form. The pure fluids are sent upwards and out to the Exterior of the body where it is used to form sweat. The impure fluids flow downwards and are excreted as urine.

    Pathology of Body Fluids
    There are 3 main pathologies of Body Fluids:

    Deficiency of Body Fluids
    • Body Fluids belong to Yin but a Deficiency of Body Fluids can precede Yin Deficiency. It can be thought of as a milder form of Yin Deficiency.
    • Deficiency of Body Fluids produces Dryness.
    • Symptoms of Dryness vary by the areas and Internal Organs affected. For example, in the Lungs the main symptoms are dry skin and dry cough. In the Kidneys the main symptoms are scanty urination and dry mouth and throat.
    • Edema is swelling of the skin and tissues caused by retention of fluids outside the cells.
    • Edema is categorized into Deficient type and Excess type.
    • Main causes of Deficiency type of Edema is Yang Qi Deficiency of various Internal Organs, especially the Lungs, Spleen and Kidneys. These types are 'pitting' which means that when the affected area is pressed, it leaves a slight indentation that lasts for a few seconds.
    • Main causes of Excess type of Edema are Qi Stagnation and Dampness retention. These types are non-pitting.
      • Phlegm is a denser, thicker form of Dampness. It is mainly formed by the condensation of fluids through exposure to a tendency for Stagnation. For example, Cold can cause Qi to congeal, stop moving, and thicken the fluids. Heat can condense fluids through vaporization.
      • There are two forms of Phlegm: Substantial and Nonsubstantial.
      • Substantial Phlegm is Phlegm that has form and can be 'seen'. This is primarily manifested as phlegm (mucus congestion) in the Lungs.
      • All other forms of Phlegm are considered Nonsubstantial. These include lumps under the skin such as nerve ganglia; swollen lymph nodes and glands; stones in the Gallbladder, Kidneys or Bladder; bone spurs and joint deformities; numbness and paralysis due to Phlegm in the Channels after a stroke; etc.
      • An important pathology of Nonsubstantial Phlegm is known as 'Phlegm Misting the Heart or Mind'. Here, Phlegm can 'obstruct the orifices of the Heart' and veil the Mind's consciousness and alertness.

    Mind (Shen)

    In the continuum of condensation of matter and Qi, from the most dense to the most rarified, the Mind is the most subtle and non-material form of Qi. It is one of the Vital Substances. As such, this concept reflects an important aspect of traditional Asian medicine's view of the integrated Mind-Body complex.

    The Mind has its roots and origins in the Essence (Jing). The Mind of an embryo and fetus comes from the Prenatal Essences of its mother and father. After birth, its Prenatal Essence is stored in the Kidneys which continue to provide the physiological and biological foundation for the Mind. But also, the newborn derives nourishment from its own Post-natal Essence produced by the Stomach and Spleen from Food-Qi.

    Thus, the close integration of the body and Mind is represented by three different states of condensation of Qi: Mind, Qi, and Essence. These three Qi's collectively are referred to as the 'Three Treasures'. The Three Treasures are related to the following three organs:
    • Mind: Heart
    • Qi: Stomach-Spleen System
    • Essence: Kidneys
    The Mind is closely related to the Heart. The Heart governs the Mind and provides it with a residence. Thus, it is the Heart that plays a primary role in the Mind's functions of fulfilling mental, emotional and sensory activities including consciousness, thinking, memory, cognition, sleep, senses, feelings and affect, etc. When the Heart is in disharmony, any or all of the foregoing activities may be affected.

    The Heart-Mind concept is in stark contrast to the Western medical view which ascribes mental functions to the realm of the brain. In the early periods of my own studies as a student of the medicine, it was difficult to reconcile the two vastly differing views. Later, I drew upon the personal conclusion that the aspect of the Mind that is housed in the Heart can be viewed as a switch or command center to the brain. Further, borrowing from modern concepts, the brain can be viewed as the mechanical relay or processing center to carry out the commands of the Heart.

    For example, it is the Heart which commands the Blood that carries nourishment to the brain. If the command center (Heart) is diseased in terms of the quantity or quality of its nourishment (Qi and Blood), the processing center will be deprived of a coherent message and disharmonies in the Mind's ascribed functions will follow.

    Interestingly, many cultures and languages have a phrase describing a 'broken heart' or 'heartache'. Perhaps those who have experienced bouts of physical pain or ache in the heart under times of extreme loss and sadness are the fortunate few who have manifested this Heart-Mind physio-emotional concept.

    Origins and Approach   |   Yin and Yang   |   Five Elements  |   Vital Substances   |   Zang-Fu Organs

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