The document describes the East Asian monsoon time scale, which is a chronological sequence used to study the past, present, and future movements of the East Asian monsoon and its relationship to weather patterns. It involves creating a graphic scale from March 21st to the following March 20th with notations for key weather events each year. Studying changes in the main rain belt and dates of monsoon onset and withdrawal over many years can provide insights into weather problems and natural disasters associated with the East Asian monsoon.