Citizens of certain countries/regions must have a short stay visa to enter Japan.
Ministry of Foreign Affairs of Japan (MOFA)
https://www.mofa.go.jp/j_info/visit/visa/index.html

If you require a visa, we advise you to obtain and submit an official Letter of Invitation from the conference organizers to help facilitate the visa process. Please note that Letters of Invitation are only issued to registered and paid/approved attendees (ONLY for Paper authors, Workshop paper authors, and Organizing and Steering committee members).

If you need an invitation letter, please contact the email below after completing your registration. (The registration site is here)

Contact address: pakdd2023@secretari.jp