Especially during the war period, it was related to Kokoku Shikan (Emperor-centered historiography which is based on state Shinto) and national policy theory, to be used as one of foundation to support government authorized idea.
特に戦中にあっては皇国史観や国体論と結び付けられて、政府公認のイデオロギーを支える基盤のひとつとして用いられた。