Thanks for applying the patch and fixing my mistake. I could not find the article of '여적 표준시 변경, 경향신문, 2000-08-14', referenced in Korean Wikipedia. But I found many articles to prove that Korea switched to UTC+9 in 1912. - http://newslibrary.naver.com/viewer/index.nhn?articleId=1954031400329203002&editNo=1&printCount=1&publishDate=1954-03-14&officeId=00032&pageNo=3&printNo=2455&publishType=00020 (This is the oldest article, in 1954) - http://www.daehansinbo.com/news/article.html?no=10992 - http://news.khan.co.kr/kh_news/khan_art_view.html?artid=201311211816081 - http://news.khan.co.kr/kh_news/khan_art_view.html?artid=201008092147425 - http://www.pressian.com/news/article.html?no=109609 - http://www.daehansinbo.com/news/article.html?no=10992 - http://article.joins.com/news/article/article.asp?total_id=15943757&cloc=olink|article|default - http://news.naver.com/main/read.nhn?mode=LSD&mid=sec&sid1=102&oid=002&aid=0001995592 And no article said that it was in 1910. Japanese annexation of Korea was started in 1910. I guess that someone may be confused between the annexation and switching timezone. And I also searched records about changes of timezone in Pyongyang, but I fail to find any meaningful articles. I agree with your assumption about Pyongyang, no change since World War II. Thank you again. -----Original Message----- From: "Paul Eggert"<eggert@cs.ucla.edu> To: "정상혁"<sanghyuk.jung@navercorp.com>; <tz@iana.org>; Cc: Sent: 2014-10-31 (금) 15:53:09 Subject: Re: [tz] [PATCH] * asia (Asia/Seoul) correct DST. Thank you. I noticed a minor error in the proposed rules, namely "Sep Sun>=20" should be "Sun Sep>=18" for 1960-09-18 to work. More important, the Wikipedia data for times before 1961 disagree with the tz database, which suggests that more corrections are needed. While we're in the neighborhood, it's completely implausible that Pyongyang faithfully mimicked Seoul time during and after the Korean war (which is what Shanks says), so let's remove that obviously-bogus guess. Attached is a proposed patch that tries to capture all this. Unfortunately I am puzzled by the Wikipedia text "1910년 4월: 동경 135° UTC+9:로 변경." This cites "여적 표준시 변경, 경향신문, 2000-08-14", a source that I cannot easily read. If Korea switched to UT+9 in April 1910, then why is there a later entry for 1912 that says "동경 135° UTC+9로 변경. 조선총독부 관보 제367 호(고시 제338호)"? That is, if Korea switched to UT+9 in 1910 why did they also switch to UT+9 in 1912? If you could clarify this point I would appreciate it. Thank you again.