Tamura Yumi is, of course, the creator of the fantastic shoujo manga series Basara (not to be confused with Sengoku Basara). Hare Tokidoki Yami is a short, poetic tragedy that she wrote in 1999.
This story is a beautiful depiction of angst, listlessness, and the sense of horror that encapsulated the post-bubble-economy in 90s Japan. There’s a very good chance that you will cry, but I would wager that it will be worth it and I don’t always feel that way.
If you’re a fan of Pink by Okazaki Kyoko, Kissxxxx by Kusumoto Maki. or works with that same combination of whimsy, social critique, and outlandish tragedy, I highly recommend reading this.