Training Difficulties
Each time he grew comfortable with negating a level of power of Sonic Singularity, he would increase the power of the domain by one percent, thereby increasing the difficulty of negating the vibrations of the technique through his yin vibrations.
Over time, hopefully, he would be able to negate the domain at full power, and that was when the yin mastery phase of the training would be completed.
The Death's Sympathy technique could allow him to project power into his body. This was perfect for training his yin vibrations because they, too, were present in the body. Thus, he could surgically exercise them with this technique.
The yin mastery in and of itself was worthy of being labeled grade-ten.
Yet it was merely the first phase.