Music video animated by Ai Niina for the song Sayonara Natsu no Hi by Tatsurou Yamashita. 
 
This music video was made in commemoration of the 30th anniversary of Yamashita's 10th studio album "ARTISAN". The song featured is a newly re-mastered recording, and was made based on the actual memories of Tatsurou Yamashita in high school, when he went to the pool at the amusement park with his girlfriend and encountered the evening sun. It is a masterpiece that best represents summer, with a small hope for the future in the longing and sentimental feelings for teens that boys and girls eventually grow up in the end. The video is composed of full-length animation by Niina, skillfully expressing the danger and fragility of youth under the theme of "time", which is a universal theme for both boys and girls. 
 
(Source: Video description, edited & translated)