A prevailant theme in Korean horror movies seems to be long, protracted suffering and prolonged scenes of grief and torture. Sure enough, Korean horror movies are almost guaranteed to focus more on the plight and anguish of the characters rather than over-the-top gore effects. Other than this, they are often indistinguishable from J-horror movies.

5 Scariest Korean Horror Movies:

Tale of Two Sisters
A Tale of Two Sisters (장화, 홍련 Janghwa, Hongryeon literally 'Rose Flower, Red Lotus') is a 2003 South Korean psychological horror film. It was directed by Kim Ji-Woon and is both the highest-grossing Korean horror film and the first to be screened in American theatres.


The film is inspired by a Joseon Dynasty folktale entitled "Janghwa Hongreyon-jon", which has been adapted to film several times.

It's a story about two girls discover a malignant force in their home while their stepmother's behavior becomes increasingly erratic...

A Tale of Two Sisters Official Website


The Phone
Phone (폰, Pon) is a 2002 South Korean horror film directed by Ahn Byeong-ki and starring Ha Ji-Won and Kim Yu-Mi. It is partly based on a popular South Korean urban legend about a high school student who commits suicide and haunts her school, playing piano when nobody is around.

In the opening sequence we see a young, frightened woman run into an elevator. Her cellphone rings, the elevator stops, and the lights flicker. She screams to be left alone, and claws at the walls...


The Quiet Family
The Quiet Family (조용한 가족, Joyonghan Gajok) is a 1998 South Korean horror-comedy film. It was director Kim Ji-Woon's feature film debut. The story centers around a family who owns a hunting lodge in a remote area, whose customers always happen to end up dying. Among the film's main cast are pre-stardom Choi Min-sik and Song Kang-ho.

The film was loosely remade as The Happiness of the Katakuris by Takashi Miike.


An extended family has moved from the city (presumably Seoul) to live in a large house out in the mountains, which they convert into a lodge for hikers. Consisting of a middle aged father Kang Dae Gu (Park In-hwa), mother Kang Soon Jae (Na Moon-hee), their brother Chang Koo (played by Choi Min Sik), and their adult children Young-min (played by Song Kang Ho), Mi-Soo (Lee Yun Sung) and Mina (played by Go Ho Kyung) they suffer a string of misfortunes as various patrons come to stay...


Whispering Corridors


Whispering Corridors (여고과담, Yeogo goedam) is a 1998 South Korean horror film about a girl's high school. It was part of the explosion in Korean cinema following the liberalization of censorship in the aftermath of the end of the country's military dictatorship, and makes a strong social commentary on authoritarianism and conformity in the harsh South Korean education system. It has inspired a number of other Korean horror films set in girls high schools and there are three direct sequels (Memento Mori, Wishing Stairs, and Voice Letter).


Whispering Corridors is set in a fairly typical all-female school in Korea, called Jookran High School For Girls, and the story begins on the night before the first day of the new school year. A female teacher called Mrs Park (better known by her unaffectionate nickname ‘Old Fox’ on account of her nasty behaviour and treatment of the students), has discovered something mysterious and weird concerning a late pupil of the school called Jin-ju. Jin-ju had committed suicide in the school’s art rooms nine years previously, and her ghost was said to haunt the art rooms which had been closed up after the incident.


Wishing Stairs

Wishing Stairs (여고과담 3: 여우계단, Yeogo goedam 3: Yeowoo gyedan) is a 2003 South Korean horror film. It is the third in a series of South Korean horror films set in girls high schools that began with 1998's Whispering Corridors, but, as with all movies in the series so far, is unrelated to the others. Similar films not in the series include Dead Friend.


The legend goes that if you climb the twenty eight steps leading up to the school dormitory, counting each step aloud, and find a twenty ninth, a spirit will appear and grant you a wish...

Another two K-Horror movies Asianoffbeat believe they are among the Scariest:

Muoi: The Legend of a Portrait


Recent Korean/Vietnamese horror movie ‘Muoi: The Legend of a Portrait’ tells a story about a Korean writer who travels to Vietnam looking for ideas to complete her second book. Her Korean friend who is living in Vietnam tells her of a century old Vietnamese legend dealing with a portrait of a woman named Muoi. Muoi means ten in Vietnamese. It is also the girl’s name in...



Cello

Cello (첼로 - 홍미주 일가 살인사건, Chello hongmijoo ilga salinsagan) is a 2005 South Korean horror film.


At the beginning we see a girl playing a cello with the music on, and in a couple of scenes we notice a girl in an operation room wearing an oxygen mask, bleeding. As the cello music goes on we see the rest of the credits and then the movie title...

Resources:
Wikipedia: K-Horror
Japundit: The Scariest K-Horror Movies of All Time