I originally nominated this for the ABBC but was told to move it here due to its difficulty level.
月曜日の友達 / Friends on Mondays
by 阿部共実 / Abe Tomomi
Summary
How far can we fly before we have to come down? Little by little, everyone in their first year of junior high school has begun their transition into adulthood. However, Akane Mizutani finds it difficult acting mature. On an off chance, she meets Tooru Tsukino, a boy in her class with mysterious rumors surrounding him—rumors that make even Mizutani think of him as strange.
With their encounter, Mizutani finds out the truth of Tsukino and the similarly odd girl Hiki. With Mizutani and Tsukino forming a promise at the schoolyard regarding each Monday night, the story depicts the relationship and encounters with each other, the alienating idea of growing up, and the truth of one’s character.
Availability
Physical
Amazon JP
Kinokuniya JP
CD Japan
Digital
Bookwalker
eBook Japan
Honto
Amazon JP (Kindle)
Personal Opinion
I’ve wanted to read this manga ever since I watched the music video for the song that Amazarashi wrote based on it. When I was having another look at it again today, I realized that it has full furigana, which gave me the idea to nominate it for the BBC. The manga is only 2 volumes long, so I think that would create a good opportunity for this club to be able to complete a whole series together (or in an offshoot club that wouldn’t take too long). I’d recommend watching the music video to see why this manga caught my interest! 
Pros and Cons for the Book Club
Pros
- Full furigana
- Slice-of-life, middle school setting, so vocabulary will probably be familiar
- Series is only 2 volumes, so finishing the whole story would be a possibility and wouldn’t take too long
- A song was inspired by it! It’s not every manga that gets that sort of treatment!
Cons
- Level 27 on Natively which seems to be on the higher end for this club. (Although whether it really is L27 is somewhat debatable, since only one Natively user gave it that grading.)
Pictures
Additional Pages
(Not sequential pages)
Around the whole first chapter is available for preview on Bookwalker, so you can check that out here if you want.