In Japanese sword making... "Nihon-to" there are usually four qualities that are valued in the blade, which can also be applied to Zen training. This is because the nature of our training is to be placed in the forge of the zendo... to work with impediments so that when both the blade and the person make contact with actual reality instead of virtual reality, neither the sword nor the person shatters AKA suffering. That said, the four qualities are sharpness, the blade's temper, harmony, and beauty.
There's an expression in Zen... "The Mind is a life-giving or death-dealing blade. What determines which is dependent upon the one that holds it."
Sharpness of blade and mind... to have the ability to see what is, and cut through without hesitation, without doubt, yet to do so with mindfulness, care, and compassion is not. To be able to do so takes time and effort. It requires a mentor... a teacher... a spiritual friend... a guide. Why? Because the nature of ego doesn't allow us to see ourselves with complete accuracy by design. For this reason, the compassionate and patient support of others can be an influencing factor between a blade or a person that shatters and one who doesn't.
The temper of the blade and mind is too hard enough to maintain sharpness, while also being flexible enough not to break or shatter in the body, mind, emotion, or spirit. Sometimes I liken Zen meditation to being a professionally trained athlete. It requires consistency, diligence, and patience to learn one's physical, mental, emotional, and spiritual mechanics of self and how they fit together. It's simple, yet it can be difficult to harmonize those elements.
The harmony of the sword and person... rather than thinking in terms of balance, is important and distinct. This became incredibly clear when I was learning kung-fu. I've come to value harmony in the blade and in the practice of zen far more than balance. Harmony allows us to be agile and, in a certain way, flow rather than struggle. What was useful for me personally was observing nature very carefully. In every instant... earth, fire, water, sky, and space operate not in balance, but in harmony.
The beauty of the Nihon... which in Zen is sometimes known as "The Form,": is the elegant and intricate design of the practice. As every aspect of a sword is given mindful attention, appreciation, and respect... so too for how we carry the bows... the hands... walk... our posture... our countenance... the placement of the cushion... the sutra books... the teacup... the elements on the walls... the altar... the lighting of the room. Everything and every thing can embody beauty.
With all of this said. If we impose hyper-perfectionism... if we're overly rigid, expecting 100% flawlessness in thoughts and feelings occurring within us, or our actions and words, and denying ourselves the freedom to meet our natural humanness and occasional messiness, in the foundry of our practice, we are bound to encounter a lot of suffering.
--We Are the Practice Itself