back and the latter along the front, divide it into left and right sides. The Yang Heel and Yin
Heel Vessels, associated with the Governing and Directing Vessels respectively, harmonize Left
and Right. Thus, there is a correspondence between Back and Left (Governing Vessel and Yang
Heel Vessel) and between Front and Right (Directing Vessel and Yin Heel Vessel). The
Governing and Directing Vessels represent the earliest embryological separation of left and right
sides of the body for, as soon as a spermatozoon penetrates the ovum, it defines the median plane
of Governing and Directing Vessels and therefore divides the body into left and right sides. As
both the Governing and Directing Vessels originate from the Kidneys and these are considered in
Chinese medicine to be the only organ with two separate viscera (the lungs being seen as one
viscus) on left and right sides, balancing Left and Right is also an important aspect of balancing
Kidney-Yin and Kidney-Yang.
The Chinese correspondence between Back and Left (Yang) and Front and Right (Yin) seems to
be confirmed by recent discoveries in palaeontology. According to these theories the ancestor of
all vertebrates (500 million years ago) was Cothurnocystis elizae, which was strikingly
asymmetrical between left and right. Its own ancestor, which lived on the sea bed, had been
perfectly symmetrical between left and right. For some reason, it flipped on its right side which
became its front, so that its left side became its back.14(578) This means that all animals that
evolved from Cothurnocystis elizae-like organisms, including vertebrates such as Man, have a
left and a right that were originally their back and front respectively. As mentioned earlier, the
human embryo determines left and right sides early in development: this has to be done if organs
are to end up functioning correctly in the appropriate sides of the body.
Left and right sides are never energetically identical as there is always an imbalance between
them. The ancient Chinese cosmology, as we have seen, attributed this to a "lack of Heaven" on
the right side and a "lack of Earth" on the left side. The Left-Right imbalance can be easily seen
on the face in the difference between the left and right eyes and ears, and in the left testicle's
being lower than the right, one kidney's being placed higher than the other, the difference in
function between left and right sides of the brain, etc.
Furthermore, Left is traditionally associated with Yang and the male element, Right with Yin
and the female element. In fact, if we look at the cycle of the 12 Earthly Branches corresponding
to the daily cycle of 24 hours, conception was thought to occur at the Earthly Branch Si (6th
Branch). If we start from the 1st Branch Zi, the male element needs to go through 30 Branches
(in order to be a multiple of 10) moving towards the left, and the female element needs to go
through 20 Branches moving towards the right, in both cases counting the starting Branch
(Figure I.14(579)). Furthermore, according to ancient Chinese ideas, pregnancy lasted 10 (lunar)
months and, if we take each Branch to correspond to a month, the female embryo moves towards
the right from the Branch Si to the Branch Shen (this branch corresponding to female, Autumn
and the number 7), and the male embryo moves towards the left from the Branch Si to the
Branch Yin (this branch corresponding to male, Spring and the number 8). The correspondence
between left and male and that between right and female are used in the balancing of opening
points of the Extraordinary Vessels and can be used for the Left-Right balancing of other