Question: When did the group debut that Kang Sung-hoon is a part of?

Context paragraphs:
Kang Sung-hoon (singer): Kang Sung-hoon (hangul:강성훈, born February 22, 1980) is a South Korean singer from the 90's South Korean boy group Sechs Kies.  Sung-hoon is the main vocalist of SechsKies and is referred to having the best singing voice of the group.  After Sechskies had disbanded in 2000, Sung-hoon pursued a solo singing career, signed under Laful Entertainment at the time.  His nickname Hoony is the title for his third album and his official fan club is called Hoony World.

Kang Sung-hoon: Kang Sung-hoon () is a Korean name consisting of the family name Kang and the given name Sung-hoon, and may also refer to:

Kang Sung-hoon (golfer): Kang Sung-hoon (Korean: 강성훈 ; born 4 June 1987) is a South Korean professional golfer who plays on the PGA Tour.

Warrior (B.A.P song): "Warrior" (Korean: 워리어) is a song recorded by South Korean boy group B.A.P.  It is released as a digital single on January 26, 2012 through TS Entertainment.  The song served as B.A.P's debut single, the first from their self-titled debut album.  "Warrior" was written and produced by Kang Ji-on and Kim Ki-bum, the same producers of Song Ji-eun's Going Crazy and Bang & Zelo's "Never Give Up".  B.A.P's leader, Bang Yong-guk also participated in the song's production by co-writing "Warrior".  The song's lyrics describes the injustice of the current society and how the protagonist's desire to end it.

Six gentlemen of the Hundred Days' Reform: The six gentlemen of the Hundred Days' Reform () refers to a group of six Chinese intellectuals whom the Empress Dowager Cixi had arrested and executed for their attempts to implement the Hundred Days' Reform.  The most vocal and prominent member in the group of six was Tan Sitong.  Kang Guangren was notable as the younger brother of the reformist leader Kang Youwei.  These executions were a part of the large purge in which about 30 men were arrested, imprisoned, dismissed from office, or banished.  In many cases the family members of these men were arrested as well.

Sechs Kies: SECHSKIES (pronounced as , Korean: 젝스키스 , Japanese: ジェクスキス ) is a six-member South Korean boy band in 1997.  They are the "1st-generation K-Pop idols" and were named as one of the top boy groups in the 90's.  Consisting of members Eun Ji-won, Lee Jai-jin, Kim Jae-duck, Kang Sung-hoon, Ko Ji-yong and Jang Su-won, the group debuted on April 15, 1997.

Kang Nam-gil: Kang Nam-gil (born August 27, 1958) is a South Korean actor.  Kang made his acting debut as a 9-year-old child actor in 1966.  He later transitioned to adult roles in 1981 with "Let Us Love" written by Kim Soo-hyun (and dropped out of Hanyang University's English Language and Literature department).  Kang drew popularity when he starred in the family drama "Under the Same Roof" in 1986, but became best known for playing "Dal-soo" in the single-episode "MBC Best Theater", which used his character to satirize the social issues of the day.  "The Trial of Dal-soo" reached 25.7% viewership ratings, the highest in the anthology series' history.  In 2000, Kang and his wife divorced on charges of adultery on her part, and his subsequent hospitalization from a heart attack led him to take a hiatus from his acting career and move with his son and daughter to England.  He returned to Korea four years later, and made his comeback with "People of the Water Flower Village".  Kang is also an author of computer books for beginners, and in 2004 he published "Oh!  My God", a memoir about his life as a stay-at-home dad in Birmingham.  In 2008, he played one of the leading roles in the spirit possession dramedy "Who Are You? ".

Han Sun-hwa: Han Sun-hwa (born October 6, 1990), is a South Korean singer and actress.  She is a former member of the South Korean girl group Secret.  She made her television debut in 2004 while participating in SBS's "Superstar Survival" as a finalist, and in 2009, she was a regular cast on a variety show called "Invincible Youth".  Aside from music, she also ventured into acting and made her debut in the 2010 drama, "More Charming By The Day".  She also acted in several dramas with supporting roles in "Ad Genius Lee Tae-baek", "God's Gift - 14 Days", and "Marriage, Not Dating".  In 2014 she finally starred as a lead actress on MBC's weekend drama "Rosy Lovers" as Baek Jang Mi co-starring with actor Lee Jang Woo.  CNN International Seoul listed Sunhwa as one of the nine rising "It" stars in Korean entertainment citing her as a "multi-tasking" artist.  Her portrayal of Kang Se-Ah in the 2014 TVN drama, "Marriage, Not Dating" earned her a nomination for "Best Youth Actress" at the 16th Seoul International Youth Film Festival.  In 2014, her portrayal of Jang-Mi from "Rosy Lovers" and Jenny from "God's Gift 14 Day"s won her two best new actress awards from MBC and SBS Drama Awards.  It was confirmed on September 26, 2016 that Sunhwa had not renewed her contract with TS Entertainment and will officially part ways in October.  On October 14, 2016 Sunhwa joined Huayi Brothers as an actress.

Krum Stoyanov: Krum Stoyanov (Bulgarian: Крум Стоянов ; born 1 August 1991) is a Bulgarian footballer who plays as a defender for Botev Plovdiv.  Stoyanov made his A Group debut for Chernomorets Burgas on 24 March 2012 against Vidima-Rakovski Sevlievo.

Kang Se-jung: Go Na-eun (born Kang Se-jung; January 15, 1982) is a South Korean actress.  She made her entertainment debut as a singer for the K-pop girl group Papaya in 2000; the group released 2 albums before disbanding in 2001.  Go began acting full-time in 2004, and has appeared in television series such as "Assorted Gems" (2009) and "Cruel City" (2013).

Supporting paragraphs: Kang Sung-hoon (singer) Sechs Kies
Answer: April 15, 1997