Koo Ja-cheol

Koo Ja-cheol ( or ; born 27 February 1989) is a South Korean professional footballer who plays for Jeju United as a midfielder.

Koo is one of the three most successful South Korean players with careers in the German Bundesliga, alongside Cha Bum-kun and Son Heung-min.

He played for VfL Wolfsburg, FC Augsburg and Mainz 05 with 211 Bundesliga appearances.

In 2006, as a member of Boin High School, Koo participated in the Baekrok High School Football Competition that is annually held in Jeju Island.

Leading Boin High School to a runner-up place with an outstanding performance, he grabbed the attention of Jung Hae-seong, who was then the manager of Jeju United.

In 2007, Koo was selected by Jeju United in the K League draft.

He failed to make an impression in his first two years at Jeju due to numerous injuries.

However, he slowly broke into the first team, mostly playing as a defensive midfielder.

In January 2010, he was reportedly invited by Blackburn Rovers for a trial, but the move didn't happen.

He spent a great season in 2010 at Jeju instead, driving his club to an unprecedented runner-up position.

His contribution also enabled him to gain personal honors such as the Top Assists Award, the FANtastic Player Award, and the Best XI.

On 30 January 2011, Koo successfully moved to VfL Wolfsburg during the winter transfer window, signing a three-and-a-half year contract for an undisclosed fee.

On 12 February 2011, Koo made his Wolfsburg debut against Hamburger SV, coming on as a substitute in the 64th minute in the 1–0 home defeat.

However, he had difficulty competing for places in the starting line-up during a year.

He also captained the South Korea national team in the 2012 Summer Olympics and the 2014 FIFA World Cup, and won a bronze medal in the Summer Olympics.

Koo started football at age ten when a nearby elementary school opened its football club.

During his early youth career, he mostly played as a defender, often taking sweeper role.

However, he wasn't particularly outstanding and the fact he suffered from anemia also hindered him from gaining attention.

On 31 January 2012, he moved on loan to the league rivals FC Augsburg.

On 18 February, he scored the equaliser outside the penalty area, but Augsburg lost 4–1 to Bayer Leverkusen.

On 17 March, he scored the equaliser with a lob outside the penalty area, and his goal contributed to a 2–1 victory against Mainz 05.

On 24 March, he assisted the equaliser, leading team's 1–1 draw against Werder Bremen.

On 31 March, he scored the opening goal with a low shot outside the penalty area, contributing to a 2–1 victory against 1. FC Köln.

On 7 April, he scored the equaliser through Manuel Neuer's legs, but his goal couldn't prevent a 2–1 loss to Bayern Munich.

On 5 May, he scored the winning goal with a header in a 1–0 victory against Hamburger SV.

During his loan period, he scored five goals and provided two assists in 15 appearances, becoming Augsburg's top goalscorer, although he played only half a season for them.

He performed a significant part in helping Augsburg to escape relegation in their maiden season in the Bundesliga.

In his second season at Augsburg, Koo was plagued by injuries, but he still helped his club survive relegation in the limited games he played in.

In a DFB-Pokal match, he was involved in an altercation with Bayern Munich's midfielder Franck Ribéry.

After a disputed free kick he confronted Ribéry and touched his face, in response Ribéry slapped Koo.

Referee Thorsten Kinhöfer gave Koo a yellow card and sent off Ribéry.

Bayern Munich director Karl-Heinz Rummenigge demanded that the ejection be overturned, while Bayern's coach Jupp Heynckes blamed both Koo and Ribéry, stating that although Koo had provoked Ribéry the latter should learn to not react under pressure.

In the 2013–14 season, he returned to Wolfsburg, and played as a central midfielder or winger.

However, he wanted more appearances, and preferred playing as an attacking midfielder like when he played for Augsburg.

On 18 January 2014, it was announced that Koo penned a four-and-a-half year deal with Mainz 05.

In the 2014–15 season, however, he was used as a winger again to replace Eric Maxim Choupo-Moting and Nicolai Müller, who left Mainz 05.

On 31 July 2014, he contributed to a 1–0 victory by assisting the winning goal against Asteras Tripoli in the third qualifying round of the 2014–15 UEFA Europa League.

On 7 August, he scored his first Europa League goal, but Mainz 05 were eliminated from the tournament after losing the second leg 3–1 to Asteras Tripoli.

He recorded five goals and two assists during 23 appearances in the 2014–15 Bundesliga.

On 31 August 2015, Koo rejoined Augsburg, and so Augsburg spent a season with three South Korean players, including Ji Dong-won and Hong Jeong-ho.