The test is named after a Japanese acupuncturist who discovered that correcting an imbalance in energy between the left and right sides of the body before you start to treat a patient helps the officials return to balance more easily. Basically, you compare the strength of energy along each meridian on the two sides of the body, and if you find any discrepancy between the two, you correct it by transferring energy from the side of the meridian which is relatively stronger to feed its weaker side. I have described the technique for doing this in my Handbook of Five Element Practice (pages 62-63).
If there is an unequal distribution of energy of this kind, it is as if the official concerned is limping to one side rather than walking straight. Akabane devised a remarkably simple method of correcting this imbalance. Doing this helps ensure that any balancing of energy through subsequent treatment is not weakened by a pre-existing tendency for a meridian to favour one side or another.
Left-right imbalances of the kind Akabane discovered can be the cause of one-sided symptoms, such as neuralgia on one side of the face, or joint pains on one side of the leg. Sometimes patients say that they feel lopsided when they walk, as if one side is weaker than the other, another sign of this imbalance. Symptoms such as these may persist, despite good treatment, if the officials concerned are struggling internally to send balanced energy down both sides of the body. It is therefore always a good idea to carry out the Akabane test and correct any imbalances found as a matter of course as part of our initial physical diagnosis.
Often several meridians can be found to be unbalanced, but I have found that correcting the one that is most out of balance can in many cases restore balance to any other imbalances that you find.