11Water

The Hello! Project shuffle units (ハロー!プロジェクト シャッフルユニット, haroo! pruojekuto shaffuru yunitto) were an annual event in the Japanese idol collection Hello! Project that spanned between 2000 and 2005. Members of existing Hello! Project groups and soloists were shuffled into three separate units for a season-long collaboration. Shuffle units formed between 2000 and 2002 released separate singles with A-side tracks of different styles but follow a common theme. Because of the nature of their releases, these units compete against each other to see which unit can sell the most singles. However, songs of the participating units in 2003 and 2005 were released together as an extended play or album, and therefore, the sales competition between units stopped. No shuffle units were formed in 2004 because then-current Hello! Project groups and soloists formed a single unit called H.P. All Starts instead.

With the disbandment of Taiyō to Ciscomoon and the graduation of Ichii and Danielle during the promotions of the releases, then-new Morning Musume members Rika Ishikawa, Hitomi Yoshizawa, Ai Kago, and Nozomi Tsuji, as well as soloist Yuki Maeda, filled in as alternates during the succeeding concerts and performances.

...
Wikipedia