The annual Hiroshima Peace Memorial Ceremony (広島平和記念式典) includes two pieces of music: the "Prayer Music No. 1: Dirge" (祈りの曲第1「哀悼歌」) by Hibakusha composer Kawasaki Masaru (川崎 優) at the start, and the "Hiroshima Peace Song" (ひろしま平和の歌) by Yamamoto Minoru (山本 秀) with lyrics by Shigezono Yoshio (重園贇雄) at the end.
For those who might want to express solidarity with the people of Hiroshima, we have transcribed/arranged both pieces, and offer the sheet music free here. These versions were principally created for pipe organ (to be played in a church), but the Peace Song is suitable for SATB choir and/or piano, and it would be easy to arrange either piece for other combinations - email us if you would like the Sibelius files (see 'Contact' above). We have looked for the actual orchestral sheet music used at the ceremony but have been unable to find it.
One request: if you do use these files in any way, please let us know - and let us have a copy of whatever you produce (e.g. a live MP3 recording, a new printed version, etc.). There are versions of both on SoundCloud, generated from MIDI files (not recorded live): Prayer Music No. 1: Dirge and Hiroshima Peace Song.