Yamagishi Riko was born on November 24, 1998 in Chiba, Japan.
She was a part of DSK Dancer's Club prior joining Hello Pro Kenshuusei.
In June 2012, Yamagishi joined Hello Pro Kenshuusei after auditioning for the program. She was officially introduced as a member on June 17 at the June 2012 recital alongside Nomura Minami. Later that summer, she participated in the Morning Musume 11ki Member "Suppin Utahime" Audition alongside several other members of Hello Pro Kenshuusei, but failed.
Begining in 2013, Yamagishi began to take part in activites outside of Hello Pro Kenshuusei starting with the Winter 2013 Hello! Project concert tour, where she was a back-dancer for several performances. She then continued participating in every Hello! Project concert tour, as well as Soto Fest and the annual Hinatsuri Festival and Countdown Lives, as a trainee, until mid-2015.
After the conclusion of the winter Hello!Con, she participated in the stage play Nettai Danshi, which ran from February 7th to February 17, 2013, alongside Kaga Kaede. On March 6th, she participated in a fanclub event for newcomers Ichioka Reina and Makino Maria.
Starting on April 2013, Yamagishi was starring on the Hello Pro Kenshuusei original webshow Hello Pro Kenshuusei no Tadaima Kenshuuchuu!. The show concluded in September. Soon after, on October 5 a new webshow titled ~Onedari Entame!~ Hapi★Pure began airing. Hapi★Pure concluded on September 27, 2014, one year after it began airing.
In fall 2013, Yamagishi participated in Morning Musume's fall 2013 tour alongside several other trainees as a back-dancer. She was later chosen to be part of the opening and challenge act for Morning Musume's fall 2014 Budokan concert, S/mileage's summer 2014 Budokan concert, Berryz Koubou's fall 2014 Budokan Concert, and ℃-ute's spring 2014 concert tour,  ℃-ute no Hi concert at Nippon Budokan and spring 2015 concert tour alongside other selected trainees.
In late 2013, Yamagishi auditioned for a role with Engeki Joshibu and passed. She starred in the Engeki Joshibu musical Bokutachi Karen na Shounen Gasshoudan, which ran from March 14 to March 23, 2014, which also features Yasuda Kei, Ogawa Makoto and several other trainees. At around the end of the year, she participated in the stage play Kurukuru to Shi to Shitto, starring Niigaki Risa and Kikkawa Yuu. The stage play ran from December 3rd to December 11, 2014.
On April 29, 2015, it was announced that Yamagishi would be debuting in a new unit named Tsubaki Factory alongside Kishimoto Yumeno, Niinuma Kisora, Asakura Kiki, Ogata Risa and Tanimoto Ami. Yamagishi's response regarding the new unit:
That I entered the Kenshuusei and then am going to debut in such short fashion makes me nervous, but when I was chosen, I was also surprised. To think that all of those that have supported me until now will be with me forever makes me happy. In Hello! Project there are a lot of groups with varied personalities, I want us to become a group that can reliably put out our personality for everyone to see.
On August 8, it was announced that Yamagishi would be the leader of Tsubaki Factory.
On November 24, Yamagishi celebrated her 19th birthday at a fanclub event titled Tsubaki Factory Yamagishi Riko Birthday Event 2017, which featured two shows at TOKYO FM HALL.
On November 26, Yamagishi celebrated her 20th birthday at a fanclub event titled Tsubaki Factory Yamagishi Riko Birthday Event 2018, which featured two shows at TOKYO FM HALL.
On November 26, she celebrated her 21st birthday at a fanclub event titled Tsubaki Factory Yamagishi Riko Birthday Event 2019, featuring two shows at TOKYO FM HALL.
On May 14, she opened up an official Instagram account.
Yamagishi was a second year middle school when she initially joined Hello Pro Kenshuusei in June 2012. When she joined Tsubaki Factory in April 2015, she was in her second year of high school. She graduated from high school in March 2017.
The following list are notable friendships Yamagishi Riko has acquired:
- Nomura Minami: She is good friends with Kobushi Factory member Nomura Minami, who she considered to be her rival in Hello Pro Kenshuusei back in December 2013 because they joined at the same time.
- Kaga Kaede: She is good friends with Morning Musume member Kaga Kaede.
- Ichioka Reina: She also is good friends with CHICA#TETSU member Ichioka Reina.
Her parents named her Riko by taking the first kanji from each of their names.
The following is a list of nicknames that have been used to refer to Yamagishi Riko:
- RikoRiko (りこりこ): Official nickname. Given to her since joining Hello Pro Kenshuusei.
- Yama (やま): Used by Ichioka Reina.
- Name: Yamagishi Riko (山岸理子)
- Official Nickname: Rikoriko (りこりこ)
- Birthday: November 24, 1998
- Birthplace: Chiba, Japan
- Blood type: B
- Height: 155cm
- Western Zodiac: Sagittarius
- Eastern Zodiac: Tiger
- Hello! Project Status:
- UP-FRONT GROUP Status:
- Tsubaki Factory Member Color: Light Green
- Hello! Project Groups:
- Shuffle Units:
- AFuRuRi (2019)
- Other Groups:
- Hobbies: Reading books, collecting pens
- Specialties: Dancing, cartwheels
- Favorite Music Genres: Hip hop, R&B, J-pop
- Favorite Sport: Badminton
- Motto: Minna chigatte, minna ii. (みんなちがって､みんないい｡; Everyone is different, everyone is good.)
- Favorite Food: Wakame egg soup, Beansprouts, grated yam, edamame, natto, ume, and fruit
- Least Favorite Food: Shiitake mushrooms, pickles carrots, sea urchin, and persimmon
- Favorite School Lunch Item: Miso cheese salad
- Favorite Colors: Yellow-green, pink
- Favorite Animal: Dogs;Miniature Dachshund, Shiba Inu, and Toy Poodle) her favorite breeds are
- Favorite Hello! Project Songs:
- (As of May 2015) "Gamusha LIFE", "Bishoujo Shinri", "Love take it all", "THE FUTURE" and "Adam to Eve no Dilemma", all by ℃-ute
- (As of November 2013) "Bagel ni Ham & Cheese" by ℃-ute, "Hatsukoi Cider" by Buono!, and "Shin•Nippon no Susume!" by S/mileage
- (In October 2016) "KEEP ON Joshou Shikou!!" by Juice=Juice,
- Favorite Tsubaki Factory Song: Teion Yakedo
- Favorite Movies: Cinderella, Biri Gal
- Favorite Anime: Chibi Maruko-chan, Sazae-san, Crayon Shin-chan, Doraemon
- Looks Up To: Suzuki Airi, Fukumura Mizuki, ℃-ute, Sasaki Rikako
- [2013-2014] ~Onedari Entame!~ Hapi★Pure
-  Nettai Danshi
-  Bokutachi Karen na Shounen Gasshoudan
-  Kurukuru to Shi to Shitto
-  Thank You Very Berry
-  Kizetsu Suru Hodo Aishiteru!
-  Zoku 11nin Iru! Higashi no Chihei, Nishi no Towa
-  Nega Poji Poji
-  Nettai Danshi (daily guest role)
-  Harukanaru Toki no Naka de 6 Gaiden ~Tasogare no Kamen~
- [2015–2019] The Girls Live
- [2019–2020] AI・DOL PROJECT (AI・DOL プロジェクト)
- [2019–2020] Hello Pro! TOKYO Sanpo (ハロプロ!TOKYO散歩)
-  Hello Dream. (ハロドリ。)
-  Hello! Project presents... "Solo Fes!"
-  Hello Pro Kenshuusei no Tadaima Kenshuuchuu!
- [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 Live Jikkyou!
-  ℃-ute - Tsugi no Kado wo Magare (as a back-up dancer)
-  ℃-ute - To Tomorrow (as a back-up dancer)
|Most airhead in Hello Pro Kenshuusei|
(March 2014 Issue of Gekkan Entame)
- She wanted to join Hello Pro Kenshuusei because she liked Minimoni when she was little.
- She thinks she won't lose to any other member in the droopiness of her eyes.
- She wants to be someone who makes everyone energetic and to be able to dance cool and sing.
- For her, the hardest thing about being a Hello Pro Kenshuusei is when she isn't chosen for things and when she feels like she hasn't improved at all.
- When asked what group she'd like to join, she answered Morning Musume. When asked again later, she said that her dream was to join a Hello Pro Kenshuusei unit.
- She wants to try singing "Crazy Kanzen na Otona" by ℃-ute.
- She sang "Kono Machi" for the Hello Pro Kenshuusei Happyoukai 2013 ~Haru no Koukai Jitsuryoku Shindan Test~ event and her number for the event was 15.
- She says that everything has gotten easier since she joined the program. She's progressed in singing and dancing and has gotten people below her. She thinks she's probably competent when it comes to rhythm but not so much with pitch. Still, she finds the lessons fun and is glad she joined the program.
- As of August 2015, she has the most theater work from the Kenshuusei.
- Fukumura Mizuki and Uemura Akari said that they are curious about Riko.
- Ever since she got her member color, she started to collect green colored items.
- Her future goal is wanting to appear in dramas and movies, and work with animals.
- She liked Minimoni.
- Gallery:Yamagishi Riko
- List:Yamagishi Riko Concert & Event Appearances
- List:Yamagishi Riko Discography Featured In
- List:Yamagishi Riko Publications Featured In
- List:Yamagishi Riko Pocket Morning Weekly Q&A
Leader of Tsubaki Factory
- ^ ^ Said during the Hello Pro Kenshuusei corner at the November 16 afternoon show of Morning Musume Concert Tour 2013 Aki ~CHANCE!~.
- ↑ "アーティスト ＞ ハロプロ研修生 ＞ プロフィール ＞ 山岸理子" (in Japanese). Hello! Project Official Site. 2014-04. (Archived: 2014-04-24).
- ↑ 2.0 2.1 2.2 "Hello Pro Kenshuusei Perfect Directory" (ハロぷろ研修生パーフェクト名鑑). BOMB Magazine, 2013-12 Issue (pg 52). Gakken Marketing. Release Date: 2013-11-09.
- ↑ "未来のハロプロ人気アイドルがここに！ハロプロ研修生発表会開催" (in Japanese). DeView. 2012-06-19.
- ↑ http://gekijyo.net/Gekipro/stage/2013/12/post-46.html
- ↑ http://www.helloproject.com/news/1588/
- ↑ "ハロプロ、今年2組目の研修生ユニット「つばきファクトリー」" (in Japanese). ORICON STYLE. 2015-04-29. Translation by MejraThea: "Tsubaki Factory Member Comments." THEA (via Tumblr). 2014-04-29.
- ↑ "ハロー！プロジェクト20周年記念「ファミハロ！PHOTOBOOK」発売決定！！" (in Japanese). Hello! Project. 2018-04-27.
- ↑ "山岸理子(つばきファクトリー)セカンド写真集「R-21」発売決定！！" (in Japanese). Hello! Project. 2020-03-27.
- ↑ "ハロー！プロジェクトメンバーオフィシャルInstagramスタート！" (in Japanese). Hello! Project. 2020-05-14.
- ↑ http://blog-project.net/yamagishi-riko/232228
- ↑ Yamagishi Riko. ""あと一週間！"山岸理子" (in Japanese). Tsubaki Factory Official Blog. 2015-05-19.
- ↑ 12.0 12.1 12.2 12.3 12.4 12.5 Yamagishi Riko. ""自己紹介の続き～" 山岸理子" (in Japanese). Tsubaki Factory Official Blog. 2015-05-18.
- ↑ ""ありがとう"山岸理子" (in Japanese). Tsubaki Factory Official Blog. 2016-04-26.
- ↑ ""卒業"山岸理子" (in Japanese). Tsubaki Factory Official Blog. 2017-03-15.
- ↑ Pocket Morning. 2016-11-06. (Translation by Ro-kun)
- ↑ 16.0 16.1 Yamagishi Riko. ""始まりましたよ〜( ¨̮ )" 山岸理子" (in Japanese). Tsubaki Factory Official Blog. 2015-05-16.
- ↑ Gekkan Entame. March 2014 Issue. Published 2014-01-30.
- Tsubaki Factory Profile
- Tsubaki Factory Official Blog
- Hello Pro Kenshuusei Blogs: September 2012, December 2012, June 2013, December 2013, 2014 Test, September 2014 (not tagged), November/December 2014, February/March 2015, Morning Musume / ℃-ute Tour Blog