Triangle (Korean: 트라이앵글; RR: Teuraiaenggeul) is a 2014 South Korean television series, starring Lee Beom-soo, Kim Jae-joong and Im Si-wan. It aired on MBC from May 5 to July 29, 2014 on Mondays and Tuesdays at 22:00 (KST) for 26 episodes.^[1][2] Triangle was directed by Yoo Cheol-yong and written by Choi Wan-kyu, who previously collaborated on the gambling dramas All In (2003) and Swallow the Sun (2009).^[3]

Separated in childhood by unfortunate circumstances, three brothers meet twenty years later, unaware of their connection to each other.^[3]

The drama achieved both domestic and international success, ranking among the most-watched dramas during its run in South Korea and its rights being sold internationally to multiple Asian countries.

Jang Dong-soo, Jang Dong-chul and Jang Dong-woo are three brothers who got separated at a young age after their father died and their mother left them. They meet again twenty years later, but unaware of their blood ties, their ill-fated paths converge on casino territory where they find themselves at odds with each other.

Eldest brother Jang Dong-soo (Lee Beom-soo) followed in the footsteps of his father and became a detective. His greatest hope is to find his two brothers again and for the siblings to finally be reunited. Due to their different approaches to crime solving, Dong-soo clashes with Hwang Shin-hye (Oh Yeon-soo), a profiler who recently returned to Korea after studying overseas. They eventually gain a mutual respect for each other as colleagues, but find themselves in conflict once again when they learn that the gangster they're after is Dong-soo's own brother, Dong-chul.

Middle brother Jang Dong-chul (Kim Jae-joong) grew up as a petty thug on the streets, using his fists and wits to survive until he climbs to the top of a crime syndicate. Now a gang boss, he conceals his real identity and uses the name Heo Young-dal.

Youngest brother Jang Dong-woo (Im Si-wan) was adopted by a rich chaebol family, and now under the name Yoon Yang-ha, is being groomed as the heir to a casino empire. With no memory of his biological family and raised believing that the world revolves around money, Yang-ha is cynical and cold-hearted. Until he meets Oh Jung-hee (Baek Jin-hee), a poor girl supporting her family by working as a casino dealer, who changes the way Yang-ha sees the world. But he has a rival for her heart, Heo Young-dal. After losing a high-stakes game of Texas hold 'em to Young-dal, Yang-ha becomes furious and lands both Young-dal and Dong-soo in jail. Upon release, the two decide to embark on a mission to get revenge on everyone who has wronged them, including Dong-woo's father, Yoon Tae-joon, the CEO of Daejung Group and Go Bok-tae (Kim Byeong-ok), the gang boss who helped Yang-ha put Young-dal in jail.

Triangle was well-received by the audience ranking among the most-watched dramas on terrestrial networks during its two-month run. It peaked at a 10.3% nationwide ratings on its final episode.

The drama was also pre-sold in Japan, China, and Thailand for a US$7 Million contract. It will be aired in the said countries in their native language.^[18]

In China, Triangle has exceeded 100 million views on Tencent; China's largest online video site, for its first 5 episodes alone, becoming one of the most-watched South Korean dramas in the country. Lead actor Kim Jae-joong's fan club in China has been broadcasting a total of 144 promotional screens at popular subway stations in Seoul since the 10th. It will be exposed for one month.

"Even If You Hate", an original soundtrack for the series, co-written and sang by Kim Jae-joong, took 2nd place on the Japanese iTunes OST chart and 4th place on the overall single chart upon release. Due to the success of the soundtrack, the singer also ranked #1 on Twitter's Hot Word and Celebrity charts while also trending on the platform.