That is, "Shido-sai" is a day on which the family head of the Sumitomo Family and the highest-ranking executive officers such as presidents, chairpersons and sodanyaku of direct affiliates of the Sumitomo Group gather once a year for the "memorial service for the deceased."
つまり「祠堂祭」は、住友家当主と住友直系企業グループの社長や会長、相談役らの最高経営責任者が、年に1度「物故者慰霊祭」のために、一堂に会する日である。