"Bach no Senritsu o Yoru ni Kiita Sei Desu" (Japanese: 『バッハの旋律を夜に聴いたせいです。』, Hepburn: Bahha no Senritsu o Yoru ni Kiita Sei Desu., IPA: [baꜜʔha no senɾitsɯ o joꜜɾɯ ɲi kiːta seꜜː desɯ̥]; "It's Because of Listening to Bach Melodies at Night") is a song by Japanese band Sakanaction.

A pop and electro song inspired by the band's vocalist Ichiro Yamaguchi experience of listening to the music of German composer Johann Sebastian Bach while falling asleep, "Bach no Senritsu o Yoru ni Kiita Sei Desu" was praised by Japanese music critics for its progression, "literary" lyrics, the integration of choral vocals and four on the floor rhythm.

[7] Yamaguchi wrote "Bach no Senritsu o Yoru ni Kiita Sei Desu" after the events of the 2011 Tōhoku earthquake and tsunami, as therapy for himself.

[9][10][11] Of all of the songs they created in this style, Yamaguchi felt that "Bach no Senritsu o Yoru ni Kiita Sei Desu" was the one that fit with this idea the most.

[8] "Years" is similarly a love song,[8] but instead of taking inspiration from everyday ideas, focused on messages reacting to the "great anxiety" in society during the post-earthquake time in Japan.

[17] As Yamaguchi felt that both songs were so similar conceptually, the band included both "Bach no Senritsu o Yoru ni Kiita Sei Desu" and "Years" on Documentaly in the same order as they appear on the single.

[8] "Bach no Senritsu o Yoru ni Kiita Sei Desu" is a pop song that blends electronic dance music and "symphonic" choral work.

[18] During a refrain in the song, a short section of Johann Sebastian Bach's Concerto I in D minor, BWV 1052, first movement is performed by Okazaki on the piano.

[26] The physical single and digital EP, in addition to "Bach no Senritsu o Yoru ni Kiita Sei Desu" and the song "Years", featured a remix of the band's song "Light Dance" by Japanese DJ Yoshinori Sunahara, as well as enhanced CD data featuring a lyric video for "Bach no Senritsu o Yoru ni Kiita Sei Desu" created with photos taken by Kamikene in Germany.

[11] On July 23, the band held a special Ustream broadcast to celebrate the single's release, shot in the studio where they were recording the album.

[30] A long interview with Yamaguchi was featured in Rockin' On Japan's August 2011 edition, where he discussed his motivations for creating music which were re-evaluated after the earthquake.

[36] In March 2013, a remix of the song by Ami Kusakari, "Bach no Senritsu o Yoru ni Kiita Sei Desu (Ks_Remix)" was featured as a bonus track on the band's sixth album Sakanaction.

Over top of the image are the words "Es ist weil ich die Musik von Bach Nachts höre" - a German language translation of the title.

During the chorus, the walls of the room open, revealing Yamaguchi behind them performing a "bar dance", with four mannequins laterally attached to him, mimicking his movements.

[44] As with the band's other music videos, they requested stylist Hisashi "Momo" Kitazawa to find a director, this time using the key words "dance" and "idiot".

Tanaka accepted, but initially felt daunted because of the high quality of the band's previous videos, however spelt his remaining time in Hawaii worried about appropriate ideas for the project.

[44] The "bar dance" was choreographed by Furitsuke Kagyou Air:Man, a group who had worked together with Sakanaction for the music video for "Native Dancer" (2009).

[52] Dai Onojima of Rockin' On Japan felt that the classical piano phrase and the choral work arrangement were very characteristic of Sakanaction.

[54] In its first week on Oricon's physical singles chart, "Bach no Senritsu o Yoru ni Kiita Sei Desu" reached number eight, selling 15,000 copies.

[55] Rival sales tracking agency SoundScan Japan found that the vast majority of copies sold in the first week were of the single's limited enhanced data edition.