ICD-11 was adopted by the World Health Organization (WHO) in 2019, and came into effect in January 2022, marking a significant transition from ICD-10. The revision process from ICD-10 to ICD-11 spanned over 30 years, resulting in a classification system that introduces numerous noteworthy changes. It will be important to become familiar with these changes brought forth by this latest revision.

To assist the understanding of these changes among the health information management personnel in Japan, a book summarising the process leading to the revision of ICD-11 and the changes from ICD-10 has been published by the Japanese Society of Medical Information Management. It summarises the ICD-11 coding tools, an overview of coding, the features of each chapter and explanations of examples. Although the Japanese version of ICD-11 is not yet completed, this book should provide many important guides for health information managers in the country.

The Japanese Society of Medical Information Management also compiled an ICD-11 coding manual and ICD-11 coding textbook. Many health information managers have used this textbook to learn and get familiar with ICD-11 coding. In addition, we held online and face-to-face workshops, and approximately 2,800 health information managers participated in the seminars. Additional ICD-11 coding workshops are scheduled this year.

Since the Japanese language version of ICD-11 has not been completed yet, we are using the English version for training of ICD-11 coding currently, and we are experiencing some difficulty in understanding the foundations exactly due to the language barrier. Yet, precise understanding of those is essential for accurate clinical coding. Further knowledge of anatomy and the other basic medical sciences are required, and we need to study more.

Implementation of ICD-11 in Japan faces some additional problems such as legislative changes required for the mortality statistics. An additional issue is the problem of the master nomenclature of diseases used for reimbursement for medical services. These are concerns that will take some work to review.

Some of the steps taken in Japan to resolve issues or problems with the implementation of ICD-11 may interest some other countries who are about to implement it.

It may take some time to get used to the new classification, but we are looking forward to health information management areas implementing and using ICD-11.



Tokiko Inagaki

Assistant Manager of the Medical Information Management Office at the Public Noto General Hospital


ICD-11 training session conducted by Tokiko Inagaki


‘ICD-11 Trajectory in Japan’ published by Tokiko Inagaki