|NND / YT (subbed)|
|Romaji||Zenmai Jikake no Komoriuta|
|English||Clockwork lullaby I|
|Release Date||March 22, 2008|
|Series||Clockwork Lullaby Series|
- "This singing voice is the clockwork lullaby."
- ―Unknown girl[src]
The song is set in an unspecified time and place. A mysterious singer, after obtaining the "key called words," begins to tie them into a song: a lullaby she wanted others to listen to, with a distinctive "Lu Li La" pattern. She also takes a toy she had always wanted and throws it out a window.
The singer questions the wishes and desires of the humankind, and she tells them to "go to sleep." She expresses uncertainty about the song healing the heart of someone with a sin of desire. Regardless, she declares that she will continue singing, believing that the memories and traumas will continue melting and blending with the song.
The song opens with an opening instrumental, and the first verse begins at 0.26, with the first pre-chorus beginning at 0.43, preceding the first chorus at 0.50. The first chorus ends at 1.09, shifting into an instrumental break which lasts until 1.24, when the second verse begins. At 1.41, the second pre-chorus begins, followed by the second chorus at 1.48. After the second chorus finishes at 2.09, another instrumental break begins, lasting until 2.40 when the final chorus begins. At 3.15, the final chorus ends, and a variation of the opening instrumental plays until the song's end.
Wordplay shares the theme of "words" continued in Clockwork Lullaby.
Re_birthday shares the "Lu Li La" pattern and its healing properties as alluded to in the Clockwork Lullaby, as well as sharing a theme of adding words to the song.
- Re_birthday's PV mirrors Clockwork Lullaby, depicting its singer in a similar pose opposite of Clockwork Lullaby's mysterious singer.
- The last line of Wordplay, "Teach me words as always", is repeated as the first line of the song.
- This is the first song to set the distinctive "lu li la" tune heard in the series' succeeding songs.