Achika yo Koyō

Achika yo Koyō [雀鳥よ泍杨; Achika and Koyō] is a early jūkyū play written by the 14th-century playwright Mizuzake no Tanyō. One of the most highly regarded jūkyū plays of the early 1400s, it is mentioned more than any other in Tanyō's repertoire, and has been depicted many times in paintings and woodcuts. There are three main characters: Achika, the son of a landowner, Koyō, the daughter of a poor farmer, and a priest named Usayami. Generally considered a romantic tale, Achika yo Koyō is based loosely on an ancient eastern Kantonese legend.
== Plot ==
The character of Koyō ('wind in the trees') is the daughter of a landowner, and is to be married to a powerful local lord; however, she yearns to travel to the capital city and live in the Imperial Court. Achika ('sparrow'), the son of a poor farmer who works on the holdings of Koyō's family, yearns to become a famous knight or warrior, in order to gain wealth and prestige. The two meet by chance during a harvest festival and fall in love. However, due to their difference in social status they are unable to marry.
The pair spend eleven months away from each other, only to meet at the next harvest festival a year later and find that their feelings have grown stronger. Koyō goes to see a wise local priest by the name of Usayami, who advises her to conduct a special ritual in order to staunch her love for Achika. During this ritual Koyō is required to empty the nearby Chōzu River of all its water; Usayami tells her that only then will her heart forget about Achika. Koyō takes a bucket and begins working for five days and five nights, until she eventually falls down in exhaustion by the bank of the river. Usayami comes to inspect her progress and remarks that she has not made even a finger of difference to the level of the river. 
Koyō revives herself and works for another five days, before her body fails her once again and she collapses in fatigue. This time, she dies by the riverbank, and the passion still simmering within her soul causes her to transform into a tall weeping willow. Achika, who is hunting in the forest, happens across the river and stops to refill his waterskin, unaware of the willow which contains the soul of his lover. Thinking of Koyō, whom he has not seen in ten days, he begins to weep. The marks of his tears upon the roots of the willow awaken Koyō's soul trapped inside, and Achika realises that she has died and reincarnated as this tree.
Grief-stricken, Achika goes to see Usayami and asks him how to overcome his own heartache. Usayami tells him to spend five days and five nights counting the blades of grass in the forest, after which time his soul will be set free. Achika tries his hardest to complete this impossible task, but after ten days of exhaustion wandering in the forest, he falls to his knees and exclaims, "If only I could fly from this place!". He then dies. Yet his soul, kept alive by the force of his determination and his love for Koyō, transforms into that of a sparrow. 
Achika, reincarnated into the body of the small bird, flies back to Koyō's willow and alights in her branches, where he stays for the rest of eternity.