If we look at the human body from a mechanical point of view, we can see that the pelvis, which is the foundation of the human body, must be kept in a horizontal position, and the legs should be of equal length so that when the spine is straight, the upper body will not bend. On the contrary, if we look carefully at the legs of people with physical lesions, they must be of different lengths, and the pelvis is not in a horizontal position. At the same time, the spine bends proportionally with the twisting of the pelvis, resulting in a skewed upper body and poor posture. Therefore, if there is an abnormal bend in the body, it has a close relationship with health. From the perspective of nerve conduction pathways and body reflexes, when the pelvis is unbalanced (not in a horizontal position), it will cause the spine to bend. The spinal nerves connected by the spinal cord include the autonomic and somatic nerves, and when the nerve compression or irritation is caused by spinal misalignment, it will cause spinal related diseases and reflex pain. Even if scoliosis occurs, it is not until the lower back and shoulders become sore that it is simply considered a muscle stiffness problem. In this regard, no matter how many partial treatments are implemented, true health cannot be achieved without correcting the skewed condition of the body as a whole and without investigating the root cause of the disease from the mechanical point of view. Therefore, the ultimate goal of Japanese hip orthopedics is to pursue the balance of the human body in three planes, namely the horizontal, sagittal and coronal planes. When the human skeleton is in the correct position, the nerves will not be compressed or stimulated, and the muscles and ligaments will not be overstretched or squeezed, so that the soreness, numbness, pain and ache can be improved. Our vertebrae support the weight of the whole body, and the pelvis is connected to the fifth lumbar vertebrae as the bottom platform of the whole spine, holding the whole spine flat and stable. When standing or walking, our pelvis is supported by our feet. The legs function like the piles of a building, serving as the foundation of our pelvis, vertebrae and skull. If our legs are not of the same length, the angle of the pelvis will be tilted, directly affecting the balance, movement and shape of the vertebrae, just as the building has long and short piles, which will produce many structural and functional problems.