Rule Sono Ichi  

rule-1, ルールそのいち, Rule No. 1, Rule Number One

Etsushi and Rio are both members of their school's archery club. While Rio is confident in his own sexuality, he keeps it hidden from others due to his young age and lack of experience with sex and romance. When they encounter each other at a gay club, it is unexpected for both of them. Etsushi is carefree and goes along with other men's desires, while Rio is more reserved. In order to maintain order at school, they establish some rules. However, rules are often meant to be broken.

Rule Sono Ichi was published digitally in English as Rule Number One by Renta! and as Rule No.1 by Torico.