CK5

In 2001, Crystal Kay started to collaborate with the hip-hop/R&B group M-Flo, with Verbal featured on her single "Ex-boyfriend", and Taku Takahashi producing her singles "Hard to Say" (2002) and "Boyfriend (Part II)" (2003).{{cite web |url=http://tower.jp/article/interview/2003/06/26/100038673/100038676 |title=両者が〈loves〉に至るまで |publisher=Tower |date=June 27, 2003 |accessdate=September 14, 2014}} In 2003, Crystal Kay collaborated on with them on two singles, "Reeewind!" and "I Like It". November saw the release of an Asia-wide English language album Crystal Kay (released as Natural in Japan) and her fourth studio album 4 Real.

In May 2004, Crystal Kay released "Motherland", a ballad written for the anime Fullmetal Alchemist, which became her second top ten single.{{cite web | title=Crystal Kayのリリース一覧 |trans-title=List of Crystal Kay's Releases | url=http://www.oricon.co.jp/prof/artist/4936/products/release/ |language=Japanese | work=Oricon | accessdate=September 12, 2014}} In June, she announced on her official website that she had graduated high school.{{cite web | url=http://www.sonymusic.co.jp/Music/Info/EPIC/artist/cry.html | title=Message from CK （2004.6.18） | language=Japanese |publisher=Sony Music Japan |archiveurl=https://web.archive.org/web/20040812014943/http://www.sonymusic.co.jp/Music/Info/EPIC/artist/cry.html |archivedate=August 12, 2004 |date=June 18, 2004 | accessdate=September 14, 2014}}

In April 2004, Crystal Kay's official site ran a poll to find out what the most popular songs of Crystal Kay's were for her fans. The resulting top 10 songs became the basis for the track list of CK5.{{cite web | url=http://www.sonymusic.co.jp/Music/Info/C-Kay/main/info.html | title=デビュー5周年企画「Your Choice of CK's best」結果発表 （2004.5.12） | language=Japanese |publisher=Sony Music Japan |archiveurl=https://web.archive.org/web/20040528075019/http://www.sonymusic.co.jp/Music/Info/C-Kay/main/info.html |archivedate=May 28, 2004 |date=May 12, 2004 | accessdate=September 14, 2014}} Three songs that were not on the list made it onto the album: "Motherland", which was the preceding single for the album, "Over the Rainbow", which was used in commercials for Tokyo Mode that featured Crystal Kay personally,{{cite web | url=http://www.sonymusic.co.jp/artist/CrystalKay/discography/ESCL-2726 | title=I LIKE IT | language=Japanese |publisher=Sony Music Japan | accessdate=September 14, 2014}} and "Lead Me to the End", which had been used as a theme song for a Fuji Television new years drama, Guchi 2.

The album compiles songs from her previously released studio albums, as well the single "Motherland". Half of the album is taken from her fourth studio 4 Real (2003) which had been released seven months ago, as well as two songs from Almost Seventeen (2002) ("Think of U" and "Hard to Say"), three from 637: Always and Forever (2001) ("Ex-Boyfriend", "Tsuki no Nai Yoru, Michi no Nai Basho" and "Lost Child") and one from C.L.L Crystal Lover Light (2000), her debut single "Eternal Memories" (1999).

The album was announced in early May, 2004.{{cite web |url=http://tower.jp/article/news/2004/05/12/100003074 |title=Crystal Kayデビュー5周年記念ベスト・アルバムをリリース |publisher=Tower |date=May 12, 2004 |accessdate=September 14, 2014}} To promote the release, Crystal Kay made appearances on radio stations throughout July, and was featured in magazines such as Nylon Japan, What's In?, CanCam, Blenda, Woofin and Teen Girl. On May 29, Crystal Kay made an appearance on the red carpet for the MTV Video Music Awards Japan 2004.{{cite web | url=http://www.sonymusic.co.jp/Music/Info/C-Kay/main/info.html | script-title=ja:最新メディア情報 （2004.6.8） | language=Japanese |publisher=Sony Music Japan |archiveurl=https://web.archive.org/web/20040528075019/http://www.sonymusic.co.jp/Music/Info/C-Kay/main/info.html |archivedate=May 28, 2004 |date=May 12, 2004 | accessdate=September 14, 2014}} On July 6, Crystal Kay performed an in-store acoustic live set at HMV Shibuya for 150 applicants who had purchased both the album and the DVD.{{cite web | url=http://www.vibe-net.com/news/?news=0018670 | title=Crystal Kay インストア・イベント出演 | language=Japanese | publisher=Vibe Net | date=June 28, 2004 | accessdate=September 14, 2014 | archive-url=https://web.archive.org/web/20140913194517/http://www.vibe-net.com/news/?news=0018670 | archive-date=September 13, 2014 | url-status=usurped }}

The album's June 30, 2004 release is one day before the five year anniversary of "Eternal Memories", which was originally released on July 1, 1999.

{{track listing

| extra_column = Arranger(s)

| total_length = 1:03:11

| title1 = Motherland

| lyrics1 = H.U.B.

| music1 = Yanagiman

| extra1 = Ken Matsubara

| length1 = 4:31

| title2 = Eternal Memories

| lyrics2 = Hiroshi Ichikura, Crystal Kay

| music2 = Yoko Kanno

| extra2 = Kanno

| length2 = 5:08

| title3 = Ex-Boyfriend

| note3 = featuring Verbal

| lyrics3 = Verbal

| music3 = T. Kura, Michico

| extra3 = T. Kura

| length3 = 5:12

| title4 = Tsuki no Nai Yoru, Michi no Nai Basho

| note4 = {{nihongo2|月のない夜 道のない場所}}, "A Moonless Night, a Pathless Place"

| lyrics4 = Saeko Nishio

| music4 = U-suke Asada

| extra4 = Asada

| length4 = 4:24

| title5 = Lost Child

| note5 = Hiroshi Fujiwara+Shinichi Osawa featuring Crystal Kay

| lyrics5 = Nishio

| music5 = Osawa, Fujiwara

| extra5 = Osawa

| length5 = 6:40

| title6 = Think of U

| lyrics6 = Crystal Kay, Nishio

| music6 = Michico, T.Kura

| extra6 = T.Kura

| length6 = 4:54

| title7 = Hard to Say

| lyrics7 = Taku Takahashi, H.U.B., Sphere of Influence, Crystal Kay

| music7 = Takahashi

| extra7 = Takahashi

| length7 = 4:50

| title8 = I Like It

| note8 = Crystal Kay loves M-Flo

| lyrics8 = M-Flo, Crystal Kay

| music8 = M-Flo, Crystal Kay

| extra8 = M-Flo

| length8 = 5:45

| title9 = Over the Rainbow

| note9 = Judy Garland cover

| lyrics9 = E.Y. Harburg

| music9 = Harold Arlen

| extra9 = Shin Kono

| length9 = 3:54

| title10 = Lead Me to the End

| lyrics10 = Masumi Kawamura

| music10 = Solaya

| extra10 = Solaya

| length10 = 4:00

| title11 = Can't Be Stopped

| lyrics11 = Nishio

| music11 = Marcus Dernulf

| extra11 = Octopussy

| length11 = 4:29

| title12 = Kataomoi

| note12 = {{nihongo2|片想い}}, "One Way Love"

| lyrics12 = Nishio, 51-Goichi-, Arkitec, Coyass

| music12 = Takahashi

| extra12 = Takahashi

| length12 = 4:24

| title13 = Boyfriend (Part II)

| lyrics13 = Nishio

| music13 = Reed Vertelney

| extra13 = Takahashi

| length13 = 5:00

}}

{{Track listing

| headline = DVD

| extra_column = Director

| title1 = Eternal Memories~Curious (live)

| extra1 =

| length1 =

}}

{{Reflist|2}}

{{Crystal Kay}}

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Category:2004 compilation albums

Category:Crystal Kay albums

Category:2000s Japanese-language albums

Category:Pop compilation albums

Category:Contemporary R&B compilation albums

Category:Epic Records compilation albums