告白ライバル宣言 (Kokuhaku Rival Sengen)

Background
It was uploaded onto Niconico Douga and YouTube on February 14, 2014. It has entered the Hall of Fame on Niconico and reached over two million views in it's YouTube upload

This song is part of Honeyworks' Confession Executive Committee Love Series. It tells the story of Koyuki, a feminine and shy boy who fell in love with Natsuki. In attempt to try winning her heart, he cut his long hair and stopped using his glasses, but even then, he didn't succeed and Natsuki confessed to Yuu, who returned her feelings. In the very end of the video, Yuu's younger sister, Hina, is seen with a love letter in hands. It was revealed in Terekakushi Shishunki that she is in love with Koyuki, and the letter is presumably for him.