Sato Masaki was born on May 7, 1999 in Hokkaido, Japan.
On September 29, Sato was selected from Morning Musume's 10th generation audition to join the group along with Iikubo Haruna, Ishida Ayumi, and former Hello Pro Egg member Kudo Haruka. The 10th generation made their official presentation on the same day they were announced as new members at the Morning Musume Concert Tour 2011 Aki Ai BELIEVE ~Takahashi Ai Sotsugyou Kinen Special~ concert, and they participated in a performance of the songs "Tomo" and "Namidacchi".
On January 13, the Morning Musume 9th generation and 10th generation members began a web talk show exclusive to fanclub members, titled Morning Musume 9ki・10ki Member WEB Talk Maji DE Pyoko!. They also began a radio show on April 7, titled Morning Musume no Morning Jogakuin ~Houkago Meeting~, on Radio Nippon.
On April 18, it was announced that Morning Musume's Tanaka Reina and the 9th and 10th generation members would participate in a new musical titled Stacies Shoujo Saisatsu Kageki. The musical ran from June 6 to June 12.
On May 13, information was released about an event featuring Morning Musume's 9th and 10th generations and S/mileage's 2nd generation, titled Mosuma FC Event ~Gachi☆Kira~. It took place throughout June and the beginning of July at Yokohama Blitz.
On May 16, the Morning Musume 9th generation and 10th generation members' fanclub-exclusive web talk show Morning Musume 9ki・10ki Member WEB Talk Maji DE Pyokopyoko! ended with a total of 70 episodes.
On May 7, Sato celebrated her 15th birthday at a fanclub event titled Morning Musume '14 ~Sato Masaki Birthday Event 2014~, which featured two shows at TOKYO FM HALL.
On May 7, Sato celebrated her 16th birthday at a fanclub event titled Morning Musume '15 Sato Masaki Birthday Event, which featured two shows at TOKYO FM HALL.
On May 20, Sato celebrated her 17th birthday at a fanclub event titled Morning Musume '16 Sato Masaki Birthday Event at Yamano Hall.
On December 22, it was announced that Sato had injured her back and was diagnosed with acute lower back pain from a lumbar herniated disc. As a result, she missed the Morning Musume '16×ANGERME FC Event "Gachi☆Kira Christmas Sen" on December 24, as well as the cheki and handshake events on December 25.
On December 28, it was announced that Sato would continue to miss the Hello! Project COUNTDOWN PARTY 2016 ~GOOD BYE & HELLO!~ concert, as well as the January 2 to January 4 shows of the Hello! Project 2017 WINTER tour due to her back injury. She would have an appointment with her doctor on January 4 to determine whether she was fit to perform again or not.
On January 6, it was announced that Sato would take a break from activities until late February. Sato had a re-examination of her lumbar disc herniation two days before, which the doctor concluded she was still not in the condition to resume performing on stage. At this time, the UP-FRONT PROMOTION representative and Sato herself revealed that she was diagnosed with a suspected lumbar disc herniation back in June 2015, but she did not have enough time for physical training. Sato did physical training throughout January as the doctor monitored the progress of her condition. In mid-February they would judge whether she could restart activities in March.
Due to being in recovery during the production period, Sato was not featured in the A-sides of Morning Musume '17's 63rd single, "BRAND NEW MORNING / Jealousy Jealousy", released on March 8. Despite this, she was featured in Limited Edition SP's exclusive B-sides.
Sato celebrated her 18th birthday at a fanclub event, titled Morning Musume '17 Sato Masaki Birthday Event, on May 8 at Differ Ariake.
On November 8 and 9, the 10th generation members of Morning Musume '17 held the Morning Days Happy Holiday 10ki Member Iikubo Haruna・Ishida Ayumi・Sato Masaki・Kudo Haruka Fanclub Tour in Yamanashi.
On March 17, Sato was featured in the graduation2018 Koukou Sotsugyou published by TOKYO NEWS magazine&mook, commemorating her and other idols' graduation from high school in 2018.
On May 7, she celebrated her 19th birthday at a fanclub event titled Morning Musume '18 Sato Masaki Birthday Event at Differ Ariake.
On March 8, it was announced that Sato would voice the recurring character Mei, the baby sister of the main character, in the NHK E Tele anime Aware! Meisaku-kun which began its fourth season on April 5.
On May 7, she celebrated her 20th birthday at a fanclub event titled Morning Musume '19 Sato Masaki Birthday Event with two shows at Shinagawa Stellar Ball.
On May 7, she was set to celebrate her 21st birthday at a fanclub event titled Morning Musume '20 Sato Masaki Birthday Event with two shows at Zepp Tokyo. It was later cancelled due to the government's declaration of emergency following the spread of the coronavirus getting worse. The event was eventually rescheduled for August 26.
She has two younger sisters, and her mother is a huge fan of Morning Musume.
On January 11, 2013, it was released that Sato Masaki, who has been resting since December 31st due to a high fever, has been diagnosed with left neck cervical lymphadenitis after a detailed examination. She was absent for all events between December 31 through January 17.
When she auditioned for Morning Musume, Sato was a 6th grade elementary school student. She started high school in April 2015 and graduated in March 2018.
On June 25, 2019, Sato wrote a blog post revealing that she had been attending university since April after candid photos of her walking down a street with another person were taken without permission and posted on Twitter. She explained that she was walking to the station ticket gate with her senior after class had ended and apologized if anyone had thought of something bad because of it. She also wrote that she would do her best at both work and studying.
Her pairing name with Kudo is MaaDuu (まぁーどぅー),
and her pairing name with Oda is MaaSaku (まぁーさく).
Sato's given name, Masaki, means "kind" (優; masa) combined with "trees" (樹; ki). Sato believes her parents chose this name for her to be a kind child.
Here is a list of nicknames that have been used to refer to Sato Masaki:
- Maa-chan (まーちゃん): Official nickname, given her since joining Morning Musume. Used by members and fans.
- Masaki (まさき): Second official nickname, given her since joining Morning Musume. Used by members and fans.
- Name: Sato Masaki (佐藤優樹)
- Nicknames: Maa-chan (まーちゃん), Masaki (まさき), MASA☆KISS (まさ☆キス), Masa (まさ), Masaking (まさキング)
- Birthdate: May 7, 1999 (age 21)
- Birthplace: Hokkaido, Japan
- Bloodtype: A
- Height: 156cm
- Western Zodiac: Taurus
- Eastern Zodiac: Rabbit
- Hello! Project Status:
- 2011-09-29: Morning Musume Member
- UP-FRONT GROUP Status:
- Years in Morning Musume: 7 Years
- Official Kaomoji: 川* ^_〉^)
- Morning Musume Color: Emerald Green
- Audition Song: "Maji Desu ka Ska!" by Morning Musume
- Hello! Project Groups:
- Concert Units:
- Hello! Project Mobekimasu (2011-2013)
- Other Groups:
- Hobbies: Playing drums, riding horses.
- Special Skills: Ballet and playing piano.
- Favorite Food: Soba, udon, plum sheets.
- Favorite Color: Yellow and green.
- Favorite Place: Disneyland.
- Philosophy: Being Smiley
- Charm Point: Eyelashes
- Motto: "Don't be noisy"
- Favorite Word: "Deshou"
- Favorite English phrase: "Thank you!"
- Favorite Morning Musume song: "Maji Desu ka Ska!", "Fantasy ga Hajimaru", "Iroppoi Jirettai"
- Past Favorite Songs: "Butterfly" by Kimura Kaela
- Current Favorite Songs: "Saraba, Itoshiki Kanashimitachi yo" by Momoiro Clover Z, "Kokuhaku" by Hirai Ken, "Robo Kiss"
- Looks Up To: Takahashi Ai, Niigaki Risa, Goto Maki, Tanaka Reina
- See also: List:Sato Masaki Discography Featured In
- [2012.07.11] Greeting ~Sato Masaki~
Solo Fanclub DVDsEdit
- [2017.09.26] Morning Musume '17 Sato Masaki Birthday Event
- [2018.09.26] Morning Musume '18 Sato Masaki Birthday Event
- [2019.09.xx] Morning Musume '19 Sato Masaki Birthday Event
-  Ou no Tsutome (from Zoku 11nin Iru! Higashi no Chihei, Nishi no Towa)
- [2018.10.06] Sankaku no Glass
- [2013.01.29] Alo-Hello! Morning Musume 2012 (アロハロ！モーニング娘。2012) (Sato Masaki version)
- [2013.04.02] Alo-Hello! Morning Musume Tenki Gumi (アロハロ！モーニング娘。天気組) (Sato Masaki version)
- [2011–2012] Hello Pro! TIME (ハロプロ！ＴＩＭＥ)
- [2012–2013] Hello! SATOYAMA Life (ハロー！ＳＡＴＯＹＡＭＡライフ)
- [2014–2019] The Girls Live
-  Hello! Project presents... "Solo Fes!"
-  Suugaku♥Joshi Gakuen (数学♥女子学園)
- [2019–] Aware! Meisaku-kun (あはれ！名作くん)
-  Stacies Shoujo Saisatsu Kageki
-  LILIUM -Lilium Shoujo Junketsu Kageki-
-  TRIANGLE
-  Zoku 11nin Iru! Higashi no Chihei, Nishi no Towa
-  Pharaoh no Haka
-  Pharaoh no Haka ~Hebi Ou Sneferu~
-  Michishige Sayumi no "Mobekimasutte Nani??"
-  Guest, Maachan (ゲスト、まぁちゃん。)
- [2013–] Hello! Project Station
- [2014–2016] MUSIC+
- [2015–2016] GREEN ROOM
- [2016–] Upcoming
- [2016–2017] Girls Night Out
- [2017–] tiny tiny
- [2018–] OMAKE CHANNEL
-  Hello Pro no Monohon!
- [2019–2020] Hello Pro no Oshigoto Challenge
-  Hello Pro Kouhaku Taiko THE☆BATTLE 2019
-  Hello Pro ONE×ONE
- [2012–2013] Morning Musume 9ki・10ki Member WEB Talk Maji DE Pyoko! (モーニング娘。9・10期メンバー WEBトーク 本気DE飛跳！) (fanclub exclusive)
- [2012–] Morning Musume no Morning Jogakuin ~Houkago Meeting~ (モーニング娘。のモーニング女学院～放課後ミーティング～)
- She was voted 6th favorite member in the 2012 "Hello! Project Music Awards" event.
- She was voted 5th favorite member in the 2013 "Hello! Project Music Awards" event.
- In Radio bangumi magazine's 7th edition "favorite DJ ranking", readers voted for her as the #1 ranked DJ on AM radio in 2014.
- She was voted most charming member of Morning Musume by Korean fans at a quiz event in Korea in 2016.
- Both Tsunku and Oda Sakura stated in separate interviews that she is a genius. In 2015, three of the 12th generation members (Ogata Haruna, Nonaka Miki, Makino Maria) also called Sato a genius.
- She is the only 10th generation member that has not had past experience in the entertainment industry.
- She spoke English until she was five years old because she grew up watching Disney Channel shows (and still watches them despite no longer understanding English). When she began kindergarten she had to start using Japanese.
- Takagi Sayuki has said that she heard that Sato can see fairies.
- Sato, Fukumura Mizuki, and Nonaka Miki are the only three Morning Musume members to be left handed.
- Her rivals are Ishida Ayumi and Oda Sakura.
- She and Suzuki Kanon are known for having perfect pitches when it comes to recognizing notes played on the piano.
- She usually forgets and stumbles on speaking lines on stage.
- She is known to be affectionate with fellow members, particularly sharing hugs with Tanaka Reina and Michishige Sayumi.
- She is afraid of chicks, which bears resemblance to Ishikawa Rika who is an ornithophobe.
- In elementary school, she was called Maasa a lot because of her name Masaki, and her resemblance to Sudo Maasa from Berryz Koubou.
- She has played the piano since she was two and has said that if she were not a member of Morning Musume, she would want to be a piano teacher. She also practiced drums starting in her third year of elementary school, but stopped in 2010.
- She is practiced to competition level obstacle jumping in horse back riding.
- She began ballet in second grade to help her fix her posture. However, by the time she became a Morning Musume member, she had already quit.
- During Morning Musume no Morning Jogakuin ~Houkago Meeting~, Sato talked admiringly about ANGERME member Sasaki Rikako.
- Michishige Sayumi said that one of her dreams is for her sister Aneshige and Sato to meet each other.
- Kudo Haruka said that Sato can communicate with aliens, while Oda Sakura finds Sato's disappearances a mystery, and believes that there is no person who could beat Sato in communication skills. Oda once said in an old interview that Sato could be the next evolution of the human race.
- Their manager asked her to make something with someone (from the management) for the 12th generation to practice their sense of rhythm. But before they could, she’d already made it all by herself: a CD of her own composition.
- Tsunku commented: "She keeps acting the youngest one, but she's quite clever. She's bad at studying, but somehow she has the ability to pull through, making her a smart girl in one way. But if she sees this she'll just think she's smart, and that's kinda scary... Work hard!"
- Oda Sakura said that Sato composes music at home like it's her side job, and even does some recording in the car.
- She uses an iPad application to create songs using drums, piano, and guitar. She added Oda Sakura's voice to a song and made her own version of "Fantasy ga Hajimaru" (Masaki Version) featuring Oda. Sato also does programmed drum beats, EDM, vocal things, key modulations.
- She had created her own song titled "Jinsei wa Iroiro Aru♪" (人生はいろいろあーる♪). When she heard that Fukumura Mizuki had become leader, she imagined Fukumura-san's face and earnestly wrote a song about her. But when it was finished, she felt embarrassed and didn't show the completed song to her. Only Oda has heard the full song.
- During handshake events she has been known to spray perfume on fans. After one event, the occurrence trended on Twitter.
- She was called "the monster overflowing with talents," in the headline of a April 2015 interview with LoGirl.
- She can imitate the singing voices of some aces and Hello! Project's best vocalists, such as Tanaka Reina, Fujimoto Miki, Sugaya Risako, and Sayashi Riho. Fans sometimes find it hard to distinguish her powerful vocals from Oda Sakura's vocals.
- Miyamoto Karin said on the au headline web show Idol Mou Icchou that Sato always says "I can't do it", but when things begin, she suddenly changes like someone else and works it out. Miyamoto thinks of herself as a hard worker who can achieve only by practice, while Sato is gifted by nature. Miyamoto declared: "I want to beat her gifted talent with my effort." The host (known as Gurasu-san, a fan of Sato as well) says Sato is in some respects a tensai (genius), which Miyamoto agreed with.
- Lyricist and musical teacher Niira Etsuko told the behind-the-scenes story about the song "Princess Margaret" from LILIUM -Lilium Shoujo Junketsu Kageki- in a YouTube video. According to her, the arrangement of the song was mostly done by Sato. The original demo was only 1:15~1:25, which Sato changed to 1:26~1:35. Niira said Sato is genius and you can't easily find someone like her in Japan. Sato was scolded for adding too much to the arrangement, but Niira says it's her fault because she's the one who approved it. Lastly, she said that changing other's work to the extent that you are scolded for it is amazing and that Sato hit the nail on the head musically. "From the point of view of normal Japanese woman or their peace-at-any-price principle, Maa-chan is the one who causes trouble... I can see why she likes Reina," she said with a laugh.
- HKT48 member Sashihara Rino is a big fan of hers. Ito Chiyuri from Team Syachihoko, Sasaki Ayaka from Momoiro Clover Z, and LingLing from BiSH are confessed fans of Sato as well
- Oda Sakura and Iikubo Haruna said that Sato mistook the lyrics in "Utakata Saturday Night!". Sato often sung the line is "ato mawashite" (後回して; put it off later) as "atama mawashite" (頭回して; turn your head), but has since begun to sing it normally. You can see her lipsync it like this in her solo version.
- Oda also said that Nonaka Miki's younger sister noticed this while watching the MV and asked Nonaka: "This part... did Sato-san sang 'atama mawashite', onee-chan?" Then they asked Sato directly and she said she really thought it was "atama mawashite".
- If she could be reborn as someone else, she would be Tsuji Nozomi. When they first met, the mama Tsuji was different from the Tsuji she saw on TV, and Sato would like to become a mother like her.
- She believes she is the most selfish Hello! Project member.
- In 20 years after 2017, Sato wants to be working beside Tsunku. She wants to teach songs to Morning Musume members, decide their concert stages and setlists, and become a producer.
- If she didn't become an idol, she would like to have become a doctor. She believes she wouldn't make a mistake if she had to operate on a family member.
- She revealed on Young Town Doyoubi that a fortune teller told her that she should graduate this year or in the next five years. But as she began to think about graduating, Ogata Haruna announced her graduation.[verification overdue]
- As a guest on Young Town Doyoubi in February 2019, Sato said she did not want to do swimsuit photos for her first photobook Sankaku no Glass because she believes it's not that different from wearing underwear and that you should only get naked for someone you love. She understands that other members do swimsuit photos because it's work and fans want to see it; however, she would want to be paid 180 million yen for it and 60 billion yen if it was for nudity.
- She is the first Morning Musume member to attend university while active in the group.
- She has the same last name as former Up Up Girls (Kari) member Sato Ayano, and former Hello Pro Kenshuusei Hokkaido member Sato Hikari.
- She shares a birthday with former Morning Musume member Konno Asami and with Juice=Juice member Dambara Ruru.
- Gallery:Sato Masaki
- Gallery:Morning Musume 10th Generation
- List:Sato Masaki Discography Featured In
- List:Sato Masaki Publications Featured In
- List:Sato Masaki Concert & Event Appearances
- List:Sato Masaki Pocket Morning Weekly Q&A
- ↑ 1.0 1.1 "モーニング娘。10期メンバー 決定！" (in Japanese). Hello! Project. 2011-09-30.
- ↑ https://twitter.com/MorningMusumeMg/status/157420658849095680
- ↑ https://twitter.com/morning1422/status/188635623681302528
- ↑ "モーニング娘。9期10期メンバー Webトーク「本気DE飛跳！」（Vol.70）」本日21時より配信♪" (in Japanese). UP-FC. 2013-05-16.
- ↑ "モーニング娘。'16 佐藤優樹についてのお知らせ" (in Japanese). Hello! Project. 2016-12-22.
- ↑ "モーニング娘。'16 佐藤優樹についてのお知らせ" (in Japanese). Hello! Project. 2016-12-28.
- ↑ "モーニング娘。'17 佐藤優樹 ステージ活動休止のお知らせ" (in Japanese). Hello! Project. 2017-01-07.
- ↑ "[EN] Concerning Masaki Sato of Morning Musume。'17." UP-FRONT LINK. 2017-01-11.
- ↑ "モーニング娘。'17 NEWシングルリリースのお知らせ" (in Japanese). Hello! Project. 2017-01-26.
- ↑ "モーニング娘。'17 佐藤優樹 ステージ活動再開のお知らせ" (in Japanese). Hello! Project. 2017-02-24.
- ↑ "[EN] Concerning the medical condition of Masaki Sato." UP-FRONT LINK. 2017-02-24.
- ↑ "graduation2018 高校卒業" (in Japanese). TOKYO NEWS magazine&mook. 2018-03-17.
- ↑ "佐藤優樹(モーニング娘。'18)ファーストビジュアルフォトブック「三角の硝子」発売決定！！" (in Japanese). Hello! Project. 2016-08-27.
- ↑ "モー娘。佐藤優樹、NHKアニメ「あはれ！名作くん」準レギュラーに！「1年かけて言葉を覚えます!!」" (in Japanese). The Television. 2019-03-08.
- ↑ "「ハロ通 PHOTOBOOK①」発売決定！！" (in Japanese). Hello! Project. 2019-08-23.
- ↑ http://www.up-fc.jp/helloproject/sp/news_Info.php?id=15485
- ↑ Sato Masaki. "皆さんへ報告 佐藤優樹" (in Japanese). Morning Musume Tenki Gumi Official Blog. 2019-06-25.
- ↑ Pocket Morning. 2016-11-01. (Translation by Ro-kun)
- ↑ 19.0 19.1 19.2 19.3 19.4 19.5 19.6 19.7 19.8 "モーニング娘。'17佐藤優樹が“20問20答”でハロプロ愛を語る！【ハロプロ誕生20周年記念連載】" (in Japanese). The Television. 2017-10-24.
- ↑ http://www.esrp2.jp/hpma/2012/result/member.html
- ↑ https://fbcdn-sphotos-c-a.akamaihd.net/hphotos-ak-prn2/1526340_707443922623809_1971311801_n.jpg
- ↑ http://i.imgur.com/2w4tEbNl.jpg
- ↑ https://youtu.be/_4nww-s_q_c?t=1794
- ↑ 24.0 24.1 24.2 "モーニング娘。'15『青春小僧が泣いている/夕暮れは雨上がり/イマココカラ』インタビュー" (in Japanese). Billboard Japan. 2015.
- ↑ "佐藤優樹（モーニング娘。）プロフィールムービー" (in Japanese). Morning Musume (via YouTube). 2012-07-02.
- ↑ Morning Musume DVD Magazine Vol.53. 2013-09-21.
- ↑ Pocket Morning Mobile App. 2014-01-09. (Translation)
- ↑ 28.0 28.1 http://helloprocanvas.ldblog.jp/archives/43275397.html
- ↑ 29.0 29.1 http://helloprocanvas.ldblog.jp/archives/43275397.html
- ↑ "「無自覚な怪物」佐藤優樹 ライブ撮りおろし＆ソロインタビュー" (in Japanese). LoGirl. 2015-04-15.
- ↑ "モーニング娘。'14 10/15発売シングル「TIKI BUN/シャバダバ ドゥ～/見返り美人」" (in Japanese). Tsunku Official Blog. 2014-08-28
- ↑ http://helloprocanvas.ldblog.jp/archives/43056602.html
- ↑ http://helloprocanvas.ldblog.jp/archives/37706146.html
- ↑ https://www.youtube.com/watch?v=ASNB5FS4jqg
- ↑ https://www.youtube.com/watch?v=craz_WKB5QU
- ↑ "HKT指原莉乃、“推しメン”モー娘。佐藤優樹との共演「職権乱用」" (in Japanese). ORICON STYLE. 2016-12-14.
- ↑ http://momo96ch.com/archives/49516868.html
- ↑ https://twitter.com/liNGliNG_BiSH/status/674203031823495172
- ↑ Morning Musume no Morning Jogakuin ~Houkago Meeting~. Radio Nippon. 2016-08-06.
- ↑ "モーニング娘。’19佐藤優樹“水着ショットの価値”が話題に「そんなに安いのは嫌だと思った」持論を展開" (in Japanese). modelpress. 2019-02-21.