Amamiya Shu transfers to Moriwaki elementary filled with hope and ambition. But it doesn't take long before he gets picked on by the class bullies, and gets involved in a dare to play the mysterious piano in the forest.
Unfortunately the movie The Piano Forest is not yet available on HBO Max.
| Directing | Masayuki Kojima | Director |
| Writing | Ryuta Hourai | Writer |
| Directing | Tomomi Yoshino | Assistant Director |
| Visual Effects | Hiroyuki Aoyama | Animation Director |
| Art | Yuko Kobayashi | Background Designer |
| Visual Effects | Seimei Maeda | Key Animation |
| Art | Yoshikatsu Matsumoto | Background Designer |
| Visual Effects | Sawako Miyamoto | Animation Director |
| Art | Sachiko Motoda | Background Designer |
| Art | Takafumi Nishima | Background Designer |
| Art | Hiroshi Nitta | Background Designer |
| Art | Park Sun-hwa | Background Designer |
| Visual Effects | Toshiharu Sugie | Key Animation |
| Visual Effects | Yoichi Takada | Key Animation |
| Visual Effects | Maki Uchida | Key Animation |
| Art | Mitsuo Yoshino | Background Designer |
| Art | Toshiharu Mizutani | Art Direction |
| Visual Effects | Wataru Abe | Key Animation |
| Visual Effects | Takahiro Ikezoe | Key Animation |
| Art | Junko Ina | Background Designer |
| Visual Effects | Masahiro Kurio | Key Animation |
| Visual Effects | Kazuyuki Matsubara | Key Animation |
| Visual Effects | Shinobu Mori | Key Animation |
| Visual Effects | Norihiro Naganuma | Key Animation |
| Art | Morihito Ohara | Background Designer |
| Art | Hayao Yoshida | Background Designer |
| Art | Yuzo Sato | Storyboard Artist |
| Visual Effects | Shigeru Fujita | Character Designer |
| Art | Kaori Hagiwara | Background Designer |
| Visual Effects | Hitomi Hasegawa | Key Animation |
| Visual Effects | Daisuke Hiramaki | Key Animation |
| Visual Effects | Tomoaki Kado | Key Animation |
| Visual Effects | Tetsuya Kawakami | Key Animation |
| Visual Effects | Eriko Kubokawa | Key Animation |
| Art | Michie Suzuki | Background Designer |
| Art | Masayuki Yamada | Background Designer |
| Art | Eri Yamanashi | Background Designer |
| Visual Effects | Shigeru Fujita | Animation Director |
| Visual Effects | Kunihiko Hamada | Animation Director |
| Visual Effects | Kouji Murai | Key Animation |
| Visual Effects | Takumo Norita | Key Animation |
| Art | Fumie Nuibe | Background Designer |
| Art | Ryusuke Shiino | Background Designer |
| Visual Effects | Yumiko Shirai | Key Animation |
| Visual Effects | Mami Yamaguchi | Key Animation |
| Art | Toshihiko Masuda | Storyboard Artist |
| Visual Effects | Kaori Aisaka | Key Animation |
| Art | Kazuo Ebisawa | Background Designer |
| Visual Effects | Hiroshi Shimizu | Animation Director |
| Visual Effects | Yuuko Sotake | Key Animation |
| Art | Tomoyuki Shimizu | Art Designer |
| Sound | Michihiko Iwana | Sound Recordist |
| Crew | Ayumi Arahata | Special Effects |
| Visual Effects | Kazutaka Hara | Key Animation |
| Art | Kei Ichikura | Background Designer |
| Art | Bo Ram Kim | Background Designer |
| Visual Effects | Mamiko Nakanishi | Key Animation |
| Art | Yoichi Nishikawa | Background Designer |
| Art | Hideyuki Ueno | Background Designer |
| Directing | Atsuko Ishizuka | Assistant Director |
| Directing | Kojiro Tsuruoka | Assistant Director |
| Visual Effects | Satomi Higuchi | Key Animation |
| Visual Effects | Hiroaki Imaki | Key Animation |
| Art | Kayoko Koitabashi | Background Designer |
| Visual Effects | Kazuhide Tomonaga | Key Animation |
| Editing | Yoshihiro Kasahara | Editor |
| Art | Nobutaka Ike | Art Designer |
| Visual Effects | Tomoko Yamamoto | Color Designer |
| Visual Effects | Takeshi Baba | Animation Director |
| Art | Kazuyo Izawa | Background Designer |
| Visual Effects | Keiko Nakaji | Key Animation |
| Art | Shiho Sato | Background Designer |
| Visual Effects | Nobumasa Shinkawa | Animation Director |
| Sound | Takeo Ogawa | Sound Designer |
| Visual Effects | Noboru Furuse | Key Animation |
| Art | Sayaka Hirahara | Background Designer |
| Visual Effects | Kaori Inoue | Key Animation |
| Visual Effects | Koichi Suenaga | Key Animation |
| Visual Effects | Teiichi Takiguchi | Animation Director |
| Sound | Kozue Okada | Music Producer |
| Art | Yuji Ikeda | Background Designer |
| Visual Effects | Hideki Ito | Key Animation |
| Visual Effects | Yoshinori Kanemori | Layout Supervisor |
| Visual Effects | Yoshinobu Michihata | Key Animation |
| Visual Effects | Tomokatsu Nagasaku | Key Animation |
| Directing | Keiko Oyamada | Assistant Director |
| Art | Akemi Konno | Art Designer |
| Art | Tadashi Kudo | Art Designer |
| Sound | Yuji Akazawa | Sound Editor |
| Visual Effects | Taichi Furumata | Key Animation |
| Art | Shuichi Tsuji | Background Designer |
| Visual Effects | Jun Uemura | Key Animation |
| Visual Effects | Aiko Wakatsuki | Key Animation |
| Visual Effects | Yuichiro Yano | Key Animation |
| Visual Effects | Hisao Yokobori | Key Animation |
| Visual Effects | Takuji Yoshimoto | Key Animation |
| Art | Kiyomi Oota | Background Designer |
| Art | Masayuki Kojima | Storyboard Artist |
| Sound | Hirokazu Ebisu | Sound Editor |
| Visual Effects | Toshiaki Iino | Key Animation |
| Art | Kazuki Ikeda | Background Designer |
| Visual Effects | Takuya Kawai | Key Animation |
| Visual Effects | Shuichi Kitayama | Key Animation |
| Visual Effects | Jun Sekiguchi | Animation Director |
| Visual Effects | Narihito Sekikawa | Key Animation |
| Art | Noriko Wada | Background Designer |
| Visual Effects | Akitoshi Yokoyama | Key Animation |
| Camera | Rumi Ishiguro | Director of Photography |
| Visual Effects | Mitsue Mori | Key Animation |
| Visual Effects | Manabu Nakatake | Key Animation |
| Art | Yoji Nakaza | Background Designer |
| Visual Effects | Hiroaki Noguchi | Animation Director |
| Visual Effects | Emiko Shimura | Key Animation |
| Visual Effects | Hideki Takahashi | Key Animation |
| Art | Seiki Tamura | Background Designer |
| Art | Kazuki Higashiji | Art Direction |
| Art | Nobuo Tomizawa | Storyboard Artist |
| Art | Yuichiro Yano | Storyboard Artist |
| Sound | Fusanobu Fujiyama | Sound Director |
| Art | Choi Kwang-Seok | Background Designer |
| Visual Effects | Chihiro Hayashi | Key Animation |
| Visual Effects | Kensuke Ishikawa | Key Animation |
| Visual Effects | Erina Kojima | Key Animation |
| Visual Effects | Tetsuro Moronuki | Key Animation |
| Art | Takashi Nakamura | Background Designer |
| Visual Effects | Tomohisa Shimoyama | Key Animation |
| Visual Effects | Satoshi Tasaki | Animation Director |
| Directing | Ryosuke Nakamura | Assistant Director |
| Directing | Toru Takahashi | Assistant Director |
| Art | Satoshi Matsudaira | Background Designer |
| Visual Effects | Michiyo Suzuki | Key Animation |
| Crew | Keiko Itogawa | Special Effects |
| Crew | Kumiko Taniguchi | Special Effects |
| Art | Toshihiro Kohama | Background Designer |
| Visual Effects | Momoko Makiuchi | Key Animation |
| Art | Yoji Takeshige | Background Designer |
| Visual Effects | Hiroya Iijima | Key Animation |
| Visual Effects | Hideoki Kusama | Key Animation |
| Visual Effects | Akira Ono | Key Animation |
| Production | Taizo Ito | Executive Producer |
| Sound | Keisuke Shinohara | Original Music Composer |
| Writing | Makoto Isshiki | Comic Book |
| Directing | Tomohiko Ito | Second Unit First Assistant Director |
| Visual Effects | Junko Miyakawa | Compositing Artist |
| Visual Effects | Yukihiko Ichikawa | Compositing Artist |
| Visual Effects | Naho Mitsuishi | Compositing Artist |
| Production | Yasuhiro Nishio | Production Assistant |
| Production | Kazuya Kamikawa | Production Assistant |
