Editing Morning Musume (section)

===2003: 6th Generation debut and sub-groups===
The unique childlike tune "[[Morning Musume no Hyokkori Hyōtanjima]]"<ref>{{Cite web|url=http://www.up-front-works.jp/discography/zetima/29/s_18/index.html|archive-url=https://web.archive.org/web/20070518045101/http://www.up-front-works.jp/discography/zetima/29/s_18/index.html|url-status=dead|title=Up-Front Works Discography – Morning Musume no Hyokkori Hyōtanjima|archive-date=May 18, 2007}}</ref> was released in February 2003 as the group's seventeenth single. It is significant because it was a cover song, marking the first time [[Tsunku]] did not write a single's lyrics.

April brought the notably successful single "[[As for One Day]]"<ref>{{Cite web|url=http://www.up-front-works.jp/discography/zetima/29/s_19/index.html|archive-url=https://web.archive.org/web/20070302100417/http://www.up-front-works.jp/discography/zetima/29/s_19/index.html|url-status=dead|title=Up-Front Works Discography – As for One Day|archive-date=March 2, 2007}}</ref>—a synthesizer-driven song about lost love—which sold 129,893 copies and hit number one in [[Oricon]] charts, and was the last time a Morning Musume single hit number one until "[[Aruiteru]]" (released late 2006). This single was the last for Kei Yasuda.

Before the auditions for the sixth generation were held, the group released the album ''[[No. 5 (Morning Musume album)|No. 5]]''.<ref>{{Cite web|url=http://www.up-front-works.jp/discography/zetima/29/a_10/index.html|archive-url=https://web.archive.org/web/20060822001225/http://www.up-front-works.jp/discography/zetima/29/a_10/index.html|url-status=dead|title=Up-Front Works Discography – No.5|archive-date=August 22, 2006}}</ref> It was unique in a few ways. It was the last studio album to feature Kei Yasuda and Natsumi Abe as full members of the group. It was also the first Morning Musume studio album to feature a former member, as Maki Goto guests on "Megami (Mousse na Yasashisa)" and "Ganbacchae!". It only featured two singles: "[[Do It! Now]]" and "[[Koko ni Iruzee!]]".

In mid-2003, four new girls were added as the sixth generation: [[Miki Fujimoto]], [[Eri Kamei]], [[Sayumi Michishige]], and [[Reina Tanaka]]. Eri Kamei, Sayumi Michishige, and Reina Tanaka successfully passed the traditional auditions; however, Miki Fujimoto was a solo singer in Hello!Project at the time. After appearing on the New Year's music program "Kōhaku Uta Gassen" with several Morning Musume members dancing as backup, Tsunku added her as part of the sixth generation.

The sixth generation's first single was "[[Shabondama (Morning Musume song)|Shabondama]]",<ref>{{Cite web|url=http://www.up-front-works.jp/discography/zetima/29/s_20/index.html|archive-url=https://web.archive.org/web/20070518045014/http://www.up-front-works.jp/discography/zetima/29/s_20/index.html|url-status=dead|title=Up-Front Works Discography – Shabondama|archive-date=May 18, 2007}}</ref> which featured "break-up" lyrics, a seemingly spontaneous dance routine, and [[alveolar trill|rolled "r"s]].

Mari Yaguchi became Morning Musume's sub-leader after Kei's departure and was also put in charge of training and assisting the trainee group of [[Hello! Project Kids]], eventually forming a group with five of them, known as [[ZYX (pop group)|ZYX]].

Later in 2003, Morning Musume was split into two subgroups so that it could tour more cities (especially smaller cities that could not support a 15-member troupe). [[Morning Musume Sakuragumi]], which focused on slower and more traditional love songs, included Natsumi Abe, Mari Yaguchi, Hitomi Yoshizawa, Ai Kago, Ai Takahashi, Risa Niigaki, Asami Konno and Eri Kamei. [[Morning Musume Otomegumi]], which had more upbeat pop songs with a slight rock flavor, featured Kaori Iida, Rika Ishikawa, Nozomi Tsuji, Makoto Ogawa, Miki Fujimoto, Sayumi Michishige, and Reina Tanaka. Sakuragumi released two singles: "[[Hare Ame Nochi Suki]]" and "[[Sakura Mankai]]", and Otomegumi released two singles as well: "[[Ai no Sono: Touch My Heart!]]" and "[[Yūjō: Kokoro no Busu ni wa Naranee!]]".

The last single of Morning Musume in 2003 to feature the entire group was "[[Go Girl: Koi no Victory]]",<ref>{{Cite web|url=http://www.up-front-works.jp/discography/zetima/29/s_21/index.html|archive-url=https://web.archive.org/web/20070227120346/http://www.up-front-works.jp/discography/zetima/29/s_21/index.html|url-status=dead|title=Up-Front Works Discography – Go Girl: Koi no Victory|archive-date=February 27, 2007}}</ref> which had the members girlishly proclaiming the victory of their love.