Simple Pulse Qualities: Depth
The deep pulse is associated with either a deficiency of yang qi to lift the pulse upward, or an obstruction to the yang qi that prevents it from rising systemically and lifting the pulse.
How do you know whether the pulse is deep due to yang deficiency or a pathogenic factor obstructing the upward movement of the pulse? If the pulse is forceless, think deficiency. If the pulse is forceful, consider the presence of an internal excessive pathogenic factor (probably cold which by nature opposes yang’s warmth.)
The superficial pulse is due to the defensive yang (wei qi) pushing the blood outward to the superficial layers in order to expel an external pathogenic factor. This pulse will likely be forceful when due to these external excesses.
However should the pulse also be thin, the pulse may be floating due to a deficiency of yin. Yin roots the pulse and prevents it from floating to the superficial level such that it lacks any depth or “root”.
Next: pulse rate.