A conjecture of different authorship presented by Biten YASUMOTO, based on the study conducted by the Institution of Statistical Mathematics in the Ministry of Education, Culture and Sports (the present Ministry of Education, Culture, Sports, Science and Technology), revealing that the frequency in the use of nouns and auxiliary verbs is different between the chapters before 'Kumogakure' and 'Ten Quires of Uji'.
別人の作説　安本美典文部省（現文部科学省）の統計数理研究所（「雲隠」までと宇治十帖の名詞と助動詞(国文法)の使用頻度が明らかに異なるという研究結果による）