For financial instruments including derivatives, ASBJ Statement No. 10, the accounting standard for financial instruments, among others, applies. Japanese GAAP centers on the standards that the ASBJ publishes with a number and a title, such as ASBJ Statement No. 30, the accounting standard for fair value measurement, and also includes standards that the Business Accounting Council published. The Regulation on Terminology, Forms and Preparation Methods of Consolidated Financial Statements says that matters it does not cover follow the corporate accounting standards generally accepted as fair and appropriate, and it counts the standards that the Business Accounting Council published among them.
To tell it apart from IFRS and US GAAP, the glossary and the articles on this site call the corporate accounting standards of Japan "Japanese GAAP."