Natsu e no TobiraNatsu e no Tobira.

Natsu e no Tobira (Japanese: 夏への扉; 'The Door into Summer') is a Japanese manga series written and illustrated by Keiko Takemiya. It is an early example of a shōnen-ai manga. It was originally serialized in Hana to Yume in 1975, published by Hakusensha, and it was re-released in 2000 by Kodansha.