One hypothesis states that tales that were included in the collection of poems of Narihira or had been handed down in his family gradually developed into the 125 chapters as we now know them, through the addition of supplementary chapters by later redactors.
元来業平の歌集や家に伝わっていた話が、後人の補足などによって段階的に現在の125段に成長していったという仮説である。