1. Department of Surgery Nara Medical University Nara Japan
2. Department of Surgery Kindai University Faculty of Medicine Osaka Japan
3. Department of Surgery Kansai Medical University Osaka Japan
4. Department of Surgery Yamagata University Graduate School of Medical Science Yamagata Japan
5. Second Department of Surgery, School of Medicine Wakayama Medical University Wakayama Japan
6. Department of Surgery Gunma Saiseikai Maebashi Hospital Maebashi Japan
7. Department of Surgery, Institute of Gastroenterology Tokyo Women's Medical University Tokyo Japan
8. Department of Hepatobiliary Pancreatic and Transplant Surgery Mie University Graduate School of Medicine Mie Japan
9. Department of Digestive Surgery, Breast and Thyroid Surgery Kagoshima University Graduate School of Medical and Dental Sciences Kagoshima Japan
10. Department of Hepatobiliary‐Pancreatic Surgery Tokyo Medical and Dental University Tokyo Japan
11. Department of Gastroenterological Surgery Hirosaki University Graduate School of Medicine Aomori Japan
12. Department of Surgery Tohoku University Graduate School of Medicine Sendai Japan
13. Department of Surgery and Oncology, Graduate School of Medical Sciences Kyushu University Fukuoka Japan
14. Project Committee Japanese Society of Hepato‐Biliary‐Pancreatic Surgery Tokyo Japan
15. Department of Gastroenterological Surgery Yokohama City University Graduate School of Medicine Kanagawa Japan