Among the many legendary writers of the ancient Japanese writings which were made from the Heian to the early Kamakura period ---most of them are not reliable, though---, these two calligraphies have signs, so they are reliable drafts for poems.
平安時代から鎌倉時代初期の古筆類は、伝称筆者は多いものの確実なものが少ない中で、この2つの書跡はともに署名があり、筆者の確実な自筆詠草である。