補 母 瀉 子 之 治 rule of repleting of mother, ​depleting the son

六 十 九 難  sixty ninth difficulty
論 補 母 explanation of rule of repleating of mother
瀉 子 之 治 and depleting the son
 
六 十 九 難 曰 ：sixty ninth difficulty says
經 言 ：treatise states
「 虛 者 補 之 ，emptyness must be supplemented
實 者 瀉 之 ， excess must be depleted
不 虛  if there is no emptiness
不 實，neither excess
以 經 取 之 。so same meridian should be used
」 何 謂 也 ？how it can be explained?
然 ： explanation
虛 者 補 其 母 ， emptiness should be supplemented by mother
實 者 瀉 其 子， excess should be depleted by son
當 先 補 乏 ，first treat repleting deficient 
然 後 瀉 之 。 afterwards treat depleting excess
不 虛  if there is no deficiency
不 實 ，neither excess
以 經 取 之 者 ， so this one meridian should be used
是 正經   used the meridian
自 生 病 ， since diseases started
不 中 他 邪 也 ， not evil will come from  other place
當 自 取 其 經 ， treat same chosen meridian
故 言 以 經 取 之 。it is why they say treat same meridian
​

69th difficult issue explains the treatment of excess and deficiency and is linked with difficulty 72
調 氣 之 方 ，direction of qi flow
必 在 陰 陽 者 ，must be yin or yang
知 其 內 外 表 裏 ， knowledge of inside and outside, external and internal
隨 其 陰 陽 而調 之 ，following yin and yang and harmonizing
故 曰 調 氣 之 方 ，way of normalizing of qi
必 在 陰 陽 。must be yin or yang
First of all difficulty explains that empty meridian should be repleted by mother meridian. For example empty heart meridian should be repleted by liver meridian
Secondly it explains that excessive meridian should be depleted by son meridian or excessive heart meridian should be depleted by spleen meridian.
當 先 補 乏 ，first treat repleting deficient
​So it explains that first should be used treatment of repleting of deficiency and depleting of excess by repleting the deficiency. First picture shows that when Lung and Liver are in excess and Heart and Spleen are deficient, we need to supplement Rong of the heart with dominating yin qi, it will deplete excessive mother-Liver and will supplement deficient son-Spleen and this dominating yin qi will easy enters yin deficient spleen meridian.
​然 後 瀉 之 。 afterwards treat depleting excess
This difficulty also explains that in the case that we can't find deficient meridian to move excess towards deficiency, we can't use heart meridian on the second picture as it is yin excessive and will not receive dominating yin. In this case practitioner should treat Wei of Lung meridian, Rong of Lung meridian is in excess, so Wei is deficient, Supplementing Wei we deplete Rong and we remove excess of Wei from Spleen meridian which Rong is deficient. So instead of Rong as in the first case we treat Wei. Wei will enter easy into lung meridian as it's rong is excessive but wei is deficient.
​不 虛  if there is no deficiency
不 實 ，neither excess
以 經 取 之 者 ， so this one meridian should be used
In the case that there is a meridian which is not affected by excess and deficiency, we may treat through this meridian as is shown on the third picture, in this case this meridian is not empty, it will not absorb dominating qi as in the first case, it is not excessive so it will not reject dominating qi as in the second case< it will just move excess from the Liver towards the Spleen following rule of Mother and Son.
​This difficulty again explains that archaic acupuncture used entire meridians to treat and not only selected acupuncture points.