This theory stands on the extensive support of the advocators who presume that Murakami-Genji (Minamoto clan) was in charge of editing this book, based upon the supposition that the original editor of this book could be the same person that enlarged the book, although the editor is said to be unidentified.
だが、これは不明とされている同書の本編作者が増補作者の一族とされる推測から本編作者を村上源氏に求める論者から広い支持があるからである。