Merry & Happy

Merry & Happy is the reissue of South Korean girl group Twice's first studio album, Twicetagram. The Christmas-inspired album was released on December 11, 2017. In addition to the original track listing, it has two new songs: the first track is titled "Heart Shaker" and the eponymous second track "Merry & Happy" was written by Park Jin-young. The album and "Heart Shaker" debuted at No. 1 on four charts of Gaon—Album Chart and Digital Chart, Download Chart and Social Chart respectively, while "Merry & Happy" entered and peaked at No. 24 on Digital Chart. Merry & Happy on Gaon Music Chart:

Twice performed both "Heart Shaker" and "Merry & Happy" on music programs—Music Bank, Show! Music Core and Inkigayo on December 15–17, respectively. The music video of "Merry & Happy" was set for release on December 21, but was uploaded online the next day instead in respect to Kim Jong-hyun, whose burial service was held on December 21.

Content production
Credits adapted from album liner notes.

Locations

 * Recording
 * JYPE Studios, Seoul, South Korea
 * Studio Instinct, Seoul, South Korea
 * E.one Sound, Seoul, South Korea
 * Heavymental Studios, Seoul, South Korea
 * NUPLAY Studio, Seoul, South Korea
 * Studio567, Seoul, South Korea
 * Banzak Studio, Seoul, South Korea


 * Mixing
 * Mirrorball Studios, North Hollywood, California
 * JYPE Studios, Seoul, South Korea
 * Studio Sean, Seoul, South Korea
 * Cube Studio, Seoul, South Korea


 * Mastering
 * Honey Butter Studio, Seoul, South Korea
 * Sterling Sound, New York City, New York
 * 821 Sound Mastering, Seoul, South Korea

Personnel

 * J. Y. Park "The Asiansoul" – producer
 * Lee Ji-young – direction and coordination (A&R)
 * Jang Ha-na – music (A&R)
 * Kim Yeo-joo (Jane Kim) – music (A&R)
 * Park Sun-hyeong – music (A&R)
 * Kim Ji-hyeong – production (A&R)
 * Choi A-ra – production (A&R)
 * Kim Je-na (Jenna Kim) – production (A&R)
 * Gong Da-yoon – production (A&R)
 * Kim Bo-hyeon – design (A&R)
 * Kim Tae-eun – design (A&R), web design, album art direction
 * Choi Hye-jin – recording, mixing and assistant mixing engineer
 * Eom Se-hee – recording and assistant mixing engineer
 * Jang Han-soo – recording and assistant mixing engineer
 * Friday of Galactika – recording engineer and chorus (on "Heart Shaker")
 * Jowul – recording engineer, vocal producer (on "Merry & Happy"), vocal director and background vocals (on "24/7")
 * Jeong Ho-hyun – recording engineer, all instruments and keyboard (on "Turtle" and "You in My Heart")
 * Earattack – recording engineer, and all instruments and computer programming (on "Missing U" and "Rollin'")
 * bass (on "Missing U"), background vocals (on "Rollin'") and director (on "Don't Give Up")
 * Jeong Gyu-chang – recording engineer
 * Kevin Oppa (mr. cho) – recording engineer, vocals producer (on "Love Line"), computer programming, piano and digital editing (on "Jaljayo Good Night")
 * Frants – recording engineer, all instruments and computer programming (on "Look at Me")
 * Tony Maserati – mixing engineer
 * James Krausse – mixing engineer
 * Lee Tae-seob – mixing engineer
 * Lim Hong-jin – mixing and assistant mixing engineer
 * Staytuned – mixing engineer
 * Yoon Won-kwon – mixing engineer
 * Jossi Ahjussi – mixing engineer
 * Jeon Bu-yeon – assistant mixing engineer
 * Bae So-yoon – assistant mixing engineer
 * Park Jeong-eon – mastering engineer
 * Chris Gehringer – mastering engineer
 * Kwon Nam-woo – mastering engineer
 * Naive Production – video director
 * Kim Young-jo – video executive producer
 * Yoo Seung-woo – video executive producer
 * Choi Pyeong-gang – video co-producer
 * Kim Young-joon at Agency SEED – photographer
 * Kang Hye-in at Normallogic – album design
 * Kang Hye-in at Normallogic – album design
 * Choi Hee-seon at F. Choi – style director
 * Son Eun-hee at Lulu – hair and makeup director
 * Jung Nan-young at Lulu – hair and makeup director
 * Choi Ji-young at Lulu – hair and makeup director
 * Jo Sang-ki at Lulu – hair and makeup director
 * Zia at Lulu – hair and makeup director
 * Jeon Dal-lae at Lulu – hair and makeup director
 * Won Jung-yo – makeup director
 * Yoon Hee-so – choreographer
 * Kang Da-sol – choreographer
 * Today Art – printing
 * David Amber – all instruments, computer programming (on "Heart Shaker")
 * Avenue 52 – all instruments, additional programming (on "Heart Shaker")
 * Galactika – vocal director (on "Heart Shaker")
 * e.Na – chorus (on "Heart Shaker")
 * Joe Lawrence – all instruments, computer programming (on "Merry & Happy")
 * Jihyo of Twice – background vocals (on "Merry & Happy", "Likey", "Ding Dong" and "Love Line")
 * Nayeon of Twice – background vocals (on "Merry & Happy" and "Likey")
 * Kim Cho-young – background vocals (on "Merry & Happy")
 * Rado – all instruments, computer programming and background vocals (on "Likey")
 * Choi Hoon – bass (on "Turtle" and "You in My Heart")
 * Yoon Tae-woong – guitar (on "Turtle" and "You in My Heart")
 * Kim Yoon-ji – chorus (on "Turtle")
 * Kim Jong-seong – guitar (on "Missing U")
 * Nam Joo – background vocals (on "Missing U", "FFW" and "Rollin'")
 * Jeong Yoo-ra at Cassette08 – digital editing (on "Missing U", "Rollin'" and "Don't Give Up")
 * Jeong Dong-hwan & Park Ji-yong & Nusoul – keyboards (on "Wow")
 * Kriz – background vocals (on "Wow")
 * Park Gi-tae – guitar (on "Wow")
 * NAOtheLAIZA – all instruments and computer programming (on "FFW")
 * Antti Hynninen – all instruments and computer programming (on "Ding Dong")
 * Caesar & Loui – all instruments and computer programming (on "24/7")
 * Oh Han-sol – background vocals (on "Look at Me")
 * Hyerim – background vocals (on "Look at Me")
 * Fox Stevenson – all instruments and computer programming (on "Rollin'")
 * Bin – background vocals (on "Rollin'" and "Don't Give Up")
 * Darren Smith – all instruments and computer programming (on "Love Line")
 * Chris Wahle – all instruments and computer programming (on "Don't Give Up")
 * Kim So-ri – chorus (on "You in My Heart")
 * Kim Jun-soo – guitar (on "Jaljayo Good Night")
 * Lee Da-jeong – background vocals (on "Jaljayo Good Night")