Last Game Series by Shinobu Amano

He's rich, he's smart, girls gather around him all the time, and he has always gotten first place on his exams... well, until Kujou transferred in his primary school class. She was quiet, plain, and poor, yet not once has she failed at beating Yanagi, both in academics and sports! Yanagi has made it his life goal to defeat this girl Kujou, and ten years later, as they enter high school, he just might finally win! This is the story of their last game.

He's rich, he's smart, girls gather around him all the time, and he has always gotten first place on his exams... well, until Kujou transferred in his primary school class. She was quiet, plain, and poor, yet not once has she failed at beating Yanagi, both in academics and sports! Yanagi has made it his life goal to defeat this girl Kujou, and ten years later, as they enter high school, he just might finally win! This is the story of their last game.

In elementary school, the rich and spoiled Yanagi Naoto ruled his class in studies and sports. But he suffered the first setback of his life when Kujou Mikoto, a girl from a poor family, transferred to his school and outperformed him at every turn. Reeling from this unforgivable blow to his pride, Naoto decided that he had to make Mikoto lose at something...by making her lose her heart to him! Now, both in college, Naoto proposes one "last game" with Mikoto--but who will be the winner?

He's rich, he's smart, girls gather around him all the time, and he has always gotten first place on his exams... well, until Kujou transferred in his primary school class. She was quiet, plain, and poor, yet not once has she failed at beating Yanagi, both in academics and sports! Yanagi has made it his life goal to defeat this girl Kujou, and ten years later, as they enter high school, he just might finally win! This is the story of their last game.

天文部で新歓合宿へ行くことになった九条と柳。事故キスしたことを意識しまくる柳をよそに、九条は無防備な態度ばかりで…。天体観測に向かう途中、柳は九条の気持ちを確かめようとするが、突然の雨で遭難して…一夜をともに!? 2013年1月刊。