Full attention should be paid during the observation, in order to grasp any details appearing on the tongue, especially the Shen or spirit of the tongue.
At the moment when the tongue is displayed, the color and movement, softness and hardness, moisture and dryness of the tongue provide reliable information for an accurate tongue-reading. The spirit of the tongue means the energy status. With enough energy, the tongue appears full of vitality with a fresh pink color, and smooth and tender. On the other hand, when there is less energy, the tongue looks weak, dull, dry, and tough.
A digital camera can be used to take pictures of the tongue, which helps one to further observe and analyze the tongue body and the coating on a computer. This is a very important step in determining the root cause of an illness.