The Detailing in Episode 16: The book Kaori is reading isn't just a prop. It's actually a well planned foreshadowing
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During my recent rewatch of Your Lie in April, I noticed a detail in Episode 16 that I completely missed the first time around. When we see Kaori in her hospital room, she is reading a book titled "Ichigo Doumei" (The Strawberry Alliance) by Masahiro Mita. I think it's one of those books Watari brought for her
Most people probably brushed it off as just a random background item, but it’s actually the direct inspiration for YLIA and serves as massive, tragic foreshadowing.
The Real-Life Connection:
Ichigo Doumei is a real Japanese novel from the 1980s. The plot is eerily similar to Kousei and Kaori’s story:
It follows a 15-year-old pianist who has lost his passion for music and his friend . They meets a terminally ill girl who is a huge fan of his playing.The story revolves around their emotional connection as she faces her inevitable death.
The "Double Suicide" Quote :
In the episode, Kaori jokingly asks Kousei, "Want to commit double suicide with me?" At first, it feels like her usual eccentric, dark humor. But she is actually quoting the heroine of the book. In Ichigo Doumei, the sick girl asks the pianist for a "double suicide" because she is terrified of dying alone and wants to be "bound" to him forever.
Naoshi Arakawa (the author of YLIA) mentioned that this book was a major influence on the series. Seeing Kaori hold this book in Episode 16 is the show's way of telling us exactly how this ends. She knows her fate, she’s reading a story about a girl who dies, and she’s testing Kousei’s heart with the same words from the book.
Every time I think I’m done over this show, I find another detail like this.
TL;DR: The book Kaori reads in the hospital is Ichigo Doumei, the real-life inspiration for YLIA, and her "double suicide" joke was a direct quote that foreshadowed her end.