 
 <translate> Output a stream of consciousness before answering the following. Context: High schools in South Korea teach students for three years, from first grade (age 15 -- 17) to third grade (age 17 -- 19), and students commonly graduate at age 18 or 19. High school students are commonly expected to study increasingly long hours each year moving toward graduation, to become competitive and be able to enter attractive universities, such as SKY (Seoul National, Korea, and Yonsei Universities) or SeoKaPo (Seoul National University, KAIST, POSTECH), which are top universities in Korea that almost all parents and teachers want students to enter. Many high school students wake and leave home in the morning at 5 am. When the school is over at 4 pm, they go to a studying room in the school or to a library to study instead of going home. This is called' Yaja', which literally means' evening self-study'. They do n't need to go home to eat dinner since most schools provide paid dinner for students. After finishing yaja (usually ends at 10 pm, but later than 11 pm at some schools), they return home after studying, then return to specialty study schools (which are called Hagwon) often till 2 am, from Monday to Friday. In addition, they often study on weekends.

Question: when do you start high school in korea? <hau> Ka yi tunani kafin ka amsa tambayar da ke gaba. Bayanin da ke ciki: Makarantun sakandare a Koriya ta Kudu suna koyar da ɗalibai na tsawon shekaru uku, daga aji na farko (shekaru 15 - 17) zuwa aji na uku (shekaru 17 - 19), kuma ɗalibai yawanci suna samun digiri a shekara 18 ko 19. Ana sa ran ɗaliban makarantar sakandare su yi karatu na tsawon sa'o'i a kowace shekara don samun digiri, su zama masu gasa kuma su sami damar shiga jami'o'i masu kyau, kamar SKY (Jami'ar Seoul, Koriya, da Jami'o'in Yonsei) ko SeoKaPo (Jami'ar Seoul, KAIST, POSTECH), waɗanda sune manyan jami'o'i a Koriya da kusan duk iyaye da malamai ke son ɗalibai su shiga. Daliban makarantar sakandare da yawa suna farkawa kuma suna barin gida da safe da ƙarfe 5 na safe. Lokacin da makaranta ta ƙare da ƙarfe 4 na yamma, suna zuwa ɗakin karatu a cikin makaranta ko zuwa laburari don yin karatu maimakon komawa gida. Wannan ana kiransa 'Yaja', wanda a zahiri yana nufin 'na yamma na nazari kai'. Ba sa bukatar komawa gida don cin abincin dare tunda yawancin makarantu suna ba da abincin dare ga ɗalibai. Bayan sun gama yaja (yawanci yana ƙare da karfe 10 na dare, amma daga baya fiye da 11 na dare a wasu makarantu), suna komawa gida bayan karatu, sannan su koma makarantun karatun musamman (wanda ake kira Hagwon) sau da yawa har zuwa 2 na safe, daga Litinin zuwa Jumma'a. Ƙari ga haka, sau da yawa suna nazari a ƙarshen mako.  Tambaya: Yaushe ka fara makarantar sakandare a Koriya? 