Every year, Otsuka also has her own Love is Born tour to mark the anniversary of being in the music industry and her birthday in September.
On Love is Born 5th Anniversary in 2008, Otsuka held a leg of the concert in Taiwan, where she performed a Chinese version of her song "Planetarium".
[7] For a short period of time -around late 2001- she was part of a duo called HimawaRi, along with classmate Mami Nishida.
She sent demo tapes to record labels with no positive results, until she got a call back from Avex just before her graduation from university.
This was the first time in Japanese music history a female artist was able to have two singles in the top ten in the same week.
[8] By end of March 2004, her first album, Love Punch, was released, and peaked third on the Oricon charts selling 190,265 copies in its first week.
"Kingyo Hanabi" also landed in third on the Oricon weekly chart but was able to sell 148,121 units, about 20,000 copies less than her "Happy Days" single.
It was a different version of the "Kuroge Wagyu Joshio Tan Yaki 735 Yen" track on Love Jam.
"Kuroge Wagyu Joshio Tan Yaki 680 Yen" is arranged differently in terms of music and vocals.
Otsuka released her tenth single in 2005, "Neko ni Fūsen" in middle of the year in July.
"Planetarium" was used as the insert song for the live action version of the drama Hana yori Dango.
[citation needed] In April 2006, Otsuka released "Frienger" (a portmanteau of the words Friend and Ranger).
The promotional video was shot in Taiwan and was used as the commercial song for the Toshiba W41T 4 GB MP3 mobile phone.
Soon after the release of "Frienger," Otsuka reprised her role as an actress for Tokyo Friends: The Movie, which hit theaters in Japan on August 12, 2006.
Otsuka also sang the opening theme for Tokyo Friends, "Yumekui", which was released as a new single on August 2, 2006.
Two months after "Yumekui", Otsuka released another single titled "Renai Shashin" on October 25, 2006, which was used as the opening theme song for the movie Tada, Kimi o Aishiteru.
[22] The single was used as the theme song for the TBS drama Kirakira Kenshui, starring Manami Konishi and Wentz Eiji of WaT and managed to claim the third position on the Oricon charts.
Otsuka released her first best hits compilation album, titled Ai am Best, on March 28, 2007, which features 13 pre-2006 songs and their respective promotional videos.
[23] Ai am Best sold 64,396 copies on the first day and topped the Oricon charts, making it Otsuka's best selling album.
On April 11, 2007 Otsuka released a new single, "Love no Theme," as the self-created bunny rabbit character "Love-chan".
Also on September 26, Otsuka released a DVD of her Ai am Best Tour 2007, recorded at the Tokyo International Forum Hall A on July 9, 2007.
Otsuka performed at Makuhari Messe on July 7, 2007, for one of Japan's two Live Earth concerts, alongside contemporaries Kumi Koda and Ayaka.
The album features a collection of "love songs," ranging from singles to album tracks and b-sides, and will feature re-recorded versions of some tracks including a duet with Su from hip-hop band Rip Slyme on the song "Aisu x Time."
During Otsuka's hiatus from music due to her pregnancy, a new song titled "Hikari" was made available for download on October 9, 2011, through her official mobile website Love 9 Cube.
This month it was also announced that Otsuka, as a solo, would begin a tour in September to celebrate her tenth anniversary in the music industry.
[30] In July 2013, it was announced that Otsuka would be releasing her first solo single in three years, entitled "Re:Name", to celebrate her tenth anniversary.
[32][33] On December 13, 2013, a song entitled "Sakuranbo (Cocktail)", which was a self-cover version of her second single, was released digitally through the iTunes Music Store.
[38] In February 2010, it was reported by Josei Seven magazine that Otsuka was dating rapper Kazuto Otsuki (publicly known as Su, member of hip hop group Rip Slyme), with whom she collaborated in October 2009 for her song "Aisu x Time".
[39] On June 26, 2010, Otsuka announced via a message on her official Web site that she and Su had gotten married on the previous day.
[42] During her Love is Born concert held on September 11, 2010, Otsuka revealed to the audience that she was expecting her first child, and on March 24, 2011, she gave birth to a daughter.