It is important to note that a warrior who believes that one direction is not enough is a wise warrior indeed, and in the normal sense, being a one track minded person is not very smart as well. One should be open-minded in many things and should also be aware of the dangers that the world has accumulated over time. The method of Yi Chuan teaches proper use of space and gravity through a balanced body structure.
The first method of Yi Chuan is Hun Yuan Li which means "Omni-directional Combat Power." It is a training that educates the student of the six directions, and these are the front, back, left, right, down, and up. It is the fighting method that simply covers the range of 360 degrees in terms of combat. It initially excludes any signs of opening or blind spots, and without one present, it advances the fighter to a higher and superior level of combat.
The next step after Hun Yuan Li would be the Shili, and that means deeper understanding of one's strength. Li speaks of the power gained in Quan Shu, which is known as Chinese Traditional Boxing, whereas Shili is the core of Deli, which means obtaining power. When the student ventures in this practice, he or she will then experience the true power in Quan Shu. Master Yao then clarifies that Pole Standing is a very important corner stone while Shili can be a key step to the martial art. Shili is a core aspect that a disciple should understand thoroughly because it is the very context in Yi Chuan. It applies to the synchronism of the basics of the art for it to function properly, or to make it easily understandable. Due to this, Shili in standing and strengthening the core must be taught well to all the students under Yi Chuan training.
Basically, one will not function well, or at all, without the other. As the words given by Master Yao Zhong Xun mentions exactly, if not similar, to what was said, "One will not function without the other." That is why it is highly encouraged to ensure that the follower understands the importance of both Shili and Hun Yuan Li, so that every application and transition are effective as it is initiated properly into motion, or rather, in a flow of constructive movements.
Finally, there's Fali which means "outburst of power." Fali is the next step after Shili, and it requires intense training for it to be effectively applied in fighting, otherwise it will backfire or result to failure. It is highly important for Shili to come before Fali so it can be applied in Yi Chuan. After all, the main purpose of Shili is to assure that your movement will be enhanced and transferred into strength, thus your mind must be set into motion. Shili will show more balance in every action that the master or student can distinguish in feeling the body, as well as in a cautious way of reinforcement.