Classical Integrable Systems and Gauge Theory

This is an introductory survey written in Japanese on classical integrability from the viewpoint of symmetry reduction of 4-dimensional anti-self-dual Yang-Mills equations. Twistor construction methods are discussed in detail in 4-dimension. Exact local solutions are, in this article, presented in terms of quasideterminants in a compact form. Some integrable aspects in lower-dimension are clarified in the context of the reduction. Noncommutative extension and higher-dimensional extension are briefly discussed.