Editing Morning Musume (section)

===2000: Koi no Dance Site, continued commercial success and the 4th Generation===
"[[Koi no Dance Site]]" was released in early 2000,<ref>{{Cite web|url=http://www.up-front-works.jp/discography/zetima/29/s_08/index.html|archive-url=https://web.archive.org/web/20140116192405/http://www.up-front-works.jp/discography/zetima/29/s_08/index.html|url-status=dead|title=Up-Front Works Discography – Koi no Dance Site|archive-date=January 16, 2014}}</ref> reaching number two and selling over a million copies—400,000 away from reaching "Love Machine"'s success. The single had the highest 1st week sales than any other Morning Musume's singles, an enormous amount of 600,860 copies. Even with this large number, the single did not reach number one because [[Southern All Stars]]'s biggest hit single, [[Tsunami (Southern All Stars song)|Tsunami]], which sold total of 2.93 million copies, was released at the same date as Koi no Dance Site. Aya Ishiguro left the group before the single was released in order to marry [[Shinya Yamada|Shinya]], drummer of [[visual kei]] rock band [[Luna Sea]], leaving the group with seven members.

The second event of 2000 was the creation of "[[Hello! Project shuffle units|shuffle units]]", in which all members of Tsunku's then 16-member family, [[Hello! Project]], were shuffled around to form three one-time groups: [[Akagumi 4]], [[Kiiro 5]], and [[Aoiro 7]]. The idea was to battle for the highest single sales. This was achieved by Akagumi 4 which boasted [[Maki Goto]] as the lead vocals.

In March, their third studio album, ''[[3rd: Love Paradise]]''<ref>{{Cite web|url=http://www.up-front-works.jp/discography/zetima/29/a_04/index.html|archive-url=https://web.archive.org/web/20140116212635/http://www.up-front-works.jp/discography/zetima/29/a_04/index.html|url-status=dead|title=Up-Front Works Discography – 3rd-Love Paradise|archive-date=January 16, 2014}}</ref> was released. Despite having "[[Love Machine (Morning Musume song)|Love Machine]]" and "[[Koi no Dance Site]]" on its track list, it did not manage to claim the number one spot, but did sell more than 800,000 copies, making it Morning Musume's highest-selling studio album to date.

This year also brought a new generation search. The fourth generation consisted of [[Rika Ishikawa]], [[Hitomi Yoshizawa]], [[Nozomi Tsuji]], and [[Ai Kago]], lending a completely different feel to the group by adding the 12-year-old duo of Tsuji and Kago. After their debut single, "[[Happy Summer Wedding]]",<ref>{{Cite web|url=http://www.up-front-works.jp/discography/zetima/29/s_09/index.html|archive-url=https://web.archive.org/web/20140116183859/http://www.up-front-works.jp/discography/zetima/29/s_09/index.html|url-status=dead|title=Up-Front Works Discography – Happy Summer Wedding|archive-date=January 16, 2014}}</ref> (continuing the legacy of number one hits with 1,370,000 copies sold,) Sayaka Ichii left to pursue her own music career. She became the vocalist of Japanese group Cubic Cross and later married fellow member Naoki Yoshizawa (no relation to Hitomi Yoshizawa).

With Ishiguro and Ichii gone, both Tanpopo and Petitmoni revised their lineups—Hitomi Yoshizawa joined Petitmoni, and Ai Kago and Rika Ishikawa were added to Tanpopo. Meanwhile, Mari Yaguchi had started performing informally with Ai Kago and Nozomi Tsuji in concerts as [[Mini Moni]], a group tailored towards younger audiences with all the members being less than 150&nbsp;cm (about 5&nbsp;ft) tall. [[Mika Todd]] of [[Coconuts Musume]] was later added into the group and Tsunku made them official. Their debut single, "[[Minimoni Jankenpyon!]]", was a number one hit on the Oricon.

As an idol group, they were extremely successful, drawing comparisons to the popularity of former girl idol group [[Speed (Japanese band)|Speed]]. "[[I Wish (Morning Musume song)|I Wish]]"<ref>{{Cite web|url=http://www.up-front-works.jp/discography/zetima/29/s_10/index.html|archive-url=https://web.archive.org/web/20131004224226/http://www.up-front-works.jp/discography/zetima/29/s_10/index.html|url-status=dead|title=Up-Front Works Discography – I Wish|archive-date=October 4, 2013}}</ref> and "[[Renai Revolution 21]]"<ref>{{Cite web|url=http://www.up-front-works.jp/discography/zetima/29/s_11/index.html|archive-url=https://web.archive.org/web/20140420182029/http://www.up-front-works.jp/discography/zetima/29/s_11/index.html|url-status=dead|title=Up-Front Works Discography – Renai Revolution 21|archive-date=April 20, 2014}}</ref> (Yuko Nakazawa's last single) continued the trend of happy pop songs becoming staple hits for the group. Morning Musume also began their tradition of performing in musicals each year, breaking new ground as idols with their musical ''[[Love Century: Yume wa Minakerya Hajimaranai]]''.