Although my knowledge of Japanese is very limited, I will try to extract some relevant parts form the article and give some other sources. According to the references listed in the article, the periods that the Philippines (Manila) observed DST or used +9 are: 1936-10-31 24:00 to 1937-01-15 24:00 (Proclamation No. 104, Proclamation No. 126) 1941-12-15 24:00 to 1945-11-30 24:00 (Proclamation No. 789, Proclamation No. 20) 1954-04-11 24:00 to 1954-06-04 24:00 (Proclamation No. 13, Proclamation No. 33) 1977-03-27 24:00 to 1977-09-21 24:00 (Proclamation No. 1629, Proclamation No. 1641) 1990-05-21 00:00 to 1990-07-28 24:00 (National Emergency Memorandum Order No. 17, Executive Order No. 415) Proclamation No. 104, s. 1936 - Signed on October 30, 1936 https://www.officialgazette.gov.ph/1936/10/30/proclamation-no-104-s-1936/ Proclamation No. 126. s. 1937 - Signed on January 15, 1937 https://www.officialgazette.gov.ph/1937/01/15/proclamation-no-126-s-1937/ Proclamation No. 789, s. 1941 - Signed on December 13, 1941 https://www.officialgazette.gov.ph/1941/12/13/proclamation-no-789-s-1941/ Proclamation No. 20, s. 1945 - Signed on November 11, 1945 https://www.officialgazette.gov.ph/1945/11/11/proclamation-no-20-s-1945/ Proclamation No. 13, s. 1954 - Signed on April 6, 1954 https://www.officialgazette.gov.ph/1954/04/06/proclamation-no-13-s-1954/ Proclamation No. 33, s. 1954 - Signed on June 3, 1954 https://www.officialgazette.gov.ph/1954/06/03/proclamation-no-33-s-1954/ Proclamation No. 1629, s. 1977 - Signed on March 25, 1977 https://www.officialgazette.gov.ph/1977/03/25/proclamation-no-1629-s-1977/ Proclamation No. 1641, s. 1977 - Signed on May 26, 1977 https://www.officialgazette.gov.ph/1977/05/26/proclamation-no-1641-s-1977/ National Emergency Memorandum Order No. 17, s. 1990 - Signed on May 2, 1990 https://www.officialgazette.gov.ph/1990/05/02/national-emergency-memorandum-... Executive Order No. 415, s. 1990 - Signed on July 20, 1990 https://www.officialgazette.gov.ph/1990/07/20/executive-order-no-415-s-1990/ During WWII, Proclamation No. 789 fixed two periods of DST. The first period was set to continue only until January 31, 1942. But Manila was occupied by the Japanese earlier in the month. According to the data from The Nautical Almanac and The Air Almanac, DST was observed in 1977 but not in 1978. https://books.google.com/books?id=Ub5Yi0357WAC&pg=SL1-PA21 https://books.google.com/books?id=XryQ6CrcE4EC&pg=PA263 https://books.google.com/books?id=E--3AAAAIAAJ&pg=SL1-PA21 https://books.google.com/books?id=2OIvjW_sHhoC&pg=SL1-PA21 https://books.google.com/books?id=6xEJAQAAIAAJ&pg=RA5-PA22-IA1 https://books.google.com/books?id=PfWDvqFgQfYC&pg=SL1-PA21 For the date of the adoption of standard time, Shank gives 1899-05-11. The article is not able to state the basis of that. I guess it was based on a US War Department Circular issued on that date. https://books.google.com/books?id=JZ1PAAAAYAAJ&pg=RA3-PA8 However, according to other sources, standard time was adopted on 1899-09-06. Also, the LMT was GMT+8:03:52 https://books.google.com/books?id=MOYIAQAAIAAJ&pg=PA521 https://books.google.com/books?id=lSnqqatpYikC&pg=PA21