Yasuda Kei was a second generation member of Morning Musume. Born in Chiba, Japan on December 6, 1980, she attended Kimitsu Shogyo High School in Futtsu City, Chiba Prefecture, but dropped out to pursue a career in the entertainment industry. After graduating from the group, Yasuda remained a soloist in Hello! Project until the Elder Club graduation on March 31st 2009. She is now part of Morning Musume OG.
- Name: Yasuda Kei (保田圭)
- Nickname: Kei-chan, Kemeko, "Aunty"
- Birthday: December 6, 1980
- Birth Place: Futtsu, Chiba, Japan
- Blood Type: A
- Height: 158.5 cm (5'2.4")
- Hobbies: Enjoying movies, drawing, organizing photos
- Special skills: Playing electronic organ and saxophone
- Favorite colors: Red, pink
- Favorite flowers: Roses, margarets, sunflowers
- Favorite seasons: Autumn, winter
- Favorite food: Yakiniku, soft roe, kimchee, nattou, chocolate
- Disliked food: Shallots, milk
- Favorite movies: Pulp Fiction, Charlie's Angels, Schindler's List, etc.
- Favorite words: Going my way, love
- Favorite song: Sekai ni Hitotsu Dake no Hana
- Hello! Project groups:
- Morning Musume (1998-2003)
- Shuffle units:
Yasuda Kei, along with Yaguchi Mari and Ichii Sayaka, was part of the second generation of Morning Musume. Morning Musume went on to produce another album and three more singles before Fukuda Asuka decided to graduate and Kei was given almost all of Asuka's lines in future performances of the earlier songs.
Kei and Sayaka sang a particularly catchy duet known as "Otome no Shinrigaku" (Girl's Psychology) in Morning Musume's album Second Morning and Tsunku decided to lump them together with 3rd generation member Goto Maki, creating the Morning Musume subgroup Petitmoni in 1999. After Sayaka graduated from Morning Musume and Petitmoni, Yoshizawa Hitomi was placed into the subgroup and Kei became leader.
Kei graduated in mid-2003, at the same time Morning Musume's 6th generation debuted, forming a brief 16nin lineup right before Kei left. During her graduation concert, Kei sang a new rock version of "Never Forget" and Tsunku presented her with her soloist copy of her last single with Morning Musume, "AS FOR ONE DAY." Yaguchi Mari became Morning Musume's sub-leader after Kei's graduation.
Because fellow Petitmoni member Goto Maki had also graduated, Petitmoni went though yet another new formation with Hitomi leading 5th generation's Ogawa Makoto, and Coconuts Musume's Ayaka Kimura, the two new members.
Kei is still in Hello! Project after graduation, collaborating with Nakazawa Yuko and other H!P artists on 2 Folk Songs albums. She has guest starred and emceed in Abe Natsumi's solo concerts, sang backup for Goto Maki's single "Daite Yo! Please Go On," and was host of Morning Musume's weekly TV show "Hello! Morning." Outside of H!P, she has worked in several dramas and musicals.
Kei is skilled in several musical instruments, including the saxophone and the piano. She has made several appearances on TV and in concert accompanying herself or others. In August 2007, she acted with Kimura Ayaka in the Otona no Mugicha play Chigaimasu Sisters.
In May 2013 Kei's upcoming marriage to Italian cuisine expert and restaurant owner Yoichi Kozaki was announced, first through newspapers and later television reports.
- TV Dramas
-  Tokio-chichi he no Dengon (トキオ 父への伝言)
-  Nijyuushi no Hitomi (二十四の瞳)
-  Sousa Ikka - Ken atari han, Takako no manako (捜査一課･見当たり班 鷹子の眼)
-  Shiawase no Jikan (幸せの時間) (as Yanagi Yuki)
-  Fuku Pika (フクピカ)
-  Shoujo-tachi no Ketsudan ~Mitchaku!! Hello! Project 20th Anniversary Audition~ (少女たちの決断~密着!!ハロー!プロジェクト20周年オーディション~)
-  Rashomon ~Onnatachi no Maboroshi~ (羅生門～女たちのまぼろし～)
-  Natsu no Yoru no Yume (夏ノ夜ノ夢; Shakespeare's "Midsummer Night's Dream")
-  Otona no Mugicha Dai kyu hai me Kouen "Nemurenaito" (大人の麦茶第九杯目公演「ネムレナイト」)
-  MAMA LOVES mambo IV
- [2010.10.07] Life is SHOWTIME! (人生はショータイム！)
- [2010.12.22-27] Abe Naikaku (安倍内閣)
-  B・B~bumpy buddy~
-  Bokutachi Karen na Shounen Gasshoudan (僕たち可憐な少年合唱団)
- [2000-2003] Young Town Douyoubi (ヤングタウン土曜日)
- [2002.03.02] Kei (圭) amazon.co.jp
- From the date she first joined (May 3, 1998) to the date she graduated (May 5, 2003), Yasuda's tenure in Morning Musume lasted 1,828 days.