In reality, Yin Cultivation had three stages: aperture cultivation, underworld communion, and gate knocking.
Aperture cultivation was divided into aperture awakening, aperture nourishment, and aperture solidification. Once cultivators had reinforced their apertures, they could attempt to open them with soul power and enter the underworld communion stage.
After achieving underworld communion, they could use soul power to build a bridge to the underworld and reach the location of that door.
In fact, gate knocking could also be considered part of the underworld communion stage. But because the changes after knocking on the door were so immense, it was singled out as a crucial milestone.
After knocking on the door in reality, one could enter the Mortal World and begin cultivating the subsequent Heaven-Ascending Steps.
However, entering the Mortal World was itself a hurdle. One might die there before even beginning the ascent.
Chen Miao had not spent particularly long on aperture cultivation. All told, it should have been about two years.
Completing aperture awakening, aperture nourishment, and aperture solidification in two years definitely counted as "blazing fast" for Yin cultivators in reality.
Yet Chen Miao himself was still somewhat dissatisfied with that time.
If matters involving the Mortal World, the Island Nation, and other things had not diverted some of his attention along the way, he could have shortened it by another three months or so.
Sensing the nine apertures within his body, Chen Miao focused most of his attention on the Heavenly Spirit Yin Aperture at the crown of his head.
He did so because it was the only aperture he had cultivated to the perfection of aperture solidification.
The Heavenly Spirit Yin Aperture was the aperture Chen Miao had used most over the past year, so its cultivation had progressed somewhat faster. The others lagged far behind.
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