The world proceeds on the balance between yin and yang.

世界在阴阳之间的平衡中前进。

The double-edged blade represented the dual nature of life, the balance between yin and yang, strength and softness, attack and defense.

双刃剑代表了生命的双重性，阴阳、刚柔、攻守的平衡。

In ancient times, it was believed that on this day, the length of the day and night was equal, and the sun was at the midpoint of the celestial equator, creating a balance between yin and yang.

古人认为这一天昼夜等长，太阳在赤道中点，阴阳平衡。