Earlier this week Mainichi Japan published an article describing some criticism of reintroducing DST to Japan. My favorite quote was this one, abut the time and cost to reprogram computers: "The biggest hurdle in Japan to putting daylight saving time in place is the cost and workload required to adjust computer systems. Professor Tetsutaro Uehara of Ritsumeikan University, a specialist in information systems, estimates that it would take about four years and hundreds of billions of yen to do just that. "'Japan is a country with advanced information technology systems, and computers with timing functions are used everywhere. Many are programmed with Japan time based on the international standard time,' pointed out Uehara. 'Software would have to be rewritten to introduce summer time. Such work would take about four years and cost hundreds of billions of yen. It is crazy to attempt to put it in place by the 2020 Games,' said the bewildered professor." My source: Nakagawa S, Hatta K. Daylight saving time causes more trouble than benefits, say critics. The Mainichi. 2018-08-12. https://mainichi.jp/english/articles/20180812/p2a/00m/0na/010000c