No is a classical Japanese dramatic form whose origins date from before 1400 A.D. Combining the elements of dance movement, music and drama with the visual elements of costumes, masks, and staging, it has a number of strict rules and conventions that are followed in its presentation. Individually, these rules and conventions are not particularly difficult to understand or execute—or at least they appear quite simple. In fact, however, the energy and concentration put into these seemingly simple movements and patterns, along with their vast numbers, interlocking and overlapping, interdependent and independent, can make the entire performance quite complex.