Tetsuya Tono, Adrian James and Matthew Yung participated in the Session on ‘Classification of Cholesteatoma and Strategy’ at the 2019 Japanese Otological Society (JOS) Conference in Yagamata, Japan. It is now apparent that the EAONO/JOS staging system and the IOOG Classification of Tympanomastoid Surgery are now being used by many Japanese and international colleagues. Adrian James presented his unpublished work on external validation of the EAONO/JOS by pooling data from nine international otology centres. Matthew Yung described his surgical strategy based on the EAONO/JOS staging system.