Waka poems were a popular art form in the Heian period, enough that the famous poet Fujiwara no Sadaie and Emperor Go-Toba sought to put together a selected collection of chosen verses.
For I could not recognize you, like 
the moon hidden behind the clouds
pues no te reconocí,
rondando cual luna tras las nubes.
Não pude reconhecê-lo,
como se fosse a lua escondida em nuvens