He managed to cultivate the first five levels of the blade technique with ease.
However, it was not as easy to advance into the sixth level.
This level required him to circulate and stimulate two strands of inner energy at the same time. It was not a difficult task Chu Li since he had the ability to multitask. The important part was where he should draw these two strands of inner energy from.
He had noticed that the power produced by the Light Blade had been rather lacking when he divided his inner energy into two parts and circulated them separately before finally letting them converge at the blade. In fact, it was weaker than the fifth level.
Clearly, there would have been some mistake in his way of performing it. These two strands of inner energy should not have come from the same source, so he needed two different types of inner energy.