Language and Difficulty:
This book is in Japanese and as far as I know, currently has no English translation. That being said, it is not a difficult read. While the story can be at times complex, the overall flow is rather simple and Saori's writing style is simple and clear. As well, it is a slice of life story, so there aren't many technical words to block even an intermediate reader from enjoying the story. I think that anybody with a solid N3 score would be capable of taking on this book with a bit of effort. However, it may not be suited for as a first attempt at reading a Japanese novel as it clocks in at just over 300 pages.
This book was an absolute joy to read, though at times troubling. Saori very skillfully portrayed the difficulties of mental illness and the potential consequences faced by Japanese youth. In Japanese, ふたご means "twins". This is reflected in the complex relationship of Natsuko and Tsukishima, who are not actually related. Natsuko, the narrator, meets Tsukishima in junior high school. He is mysterious and she is drawn to him, despite her lack of self-confidence. They grow older and their relationship becomes increasingly complex and at times problematic. Nonetheless, their story is heartwarming. I feel a strong connection with them now that I have finished the book.
As I already said, Saori has a very clear and easy to understand writing style. She chose a topic she is familiar with, music, and used it to give her characters life. This made reading the novel a pleasurable experience and gave it much more feeling. Not only that, but the setting is very close to my house. Even a tourist might be familiar with the area, Ikegami.
I picked up this book at a difficult time in my life. Therefore, I connected strongly to Natsuko. This book was definitely an eye opener for me and I cannot recommend it enough. Great for fans of of SEKAI NO OWARI and those looking to challenge themselves with reading a novel in Japanese.
Feel free to ask me any questions in the comments about where to buy the book or to give recommendations!