The bagua are eight trigrams used in Taoist cosmology to represent the fundamental principles of reality, seen as a range of eight interrelated concepts.

Each consists of three lines, each line either 'broken' or 'unbroken'', representing yin or yang, respectively. Due to their tripartite structure, they are often referred to as 'trigrams' in English.

In Chinese philosophy, yin and yang (also, yin-yang or yin yang) describes how apparently opposite or contrary forces are actually complementary, interconnected, and interdependent in the natural world, and how they give rise to each other as they interrelate to one another.