Tokyo: Management of Japanese rail company apologized sincerely after the Tsukuba Express departed from Tokyo to Tsukuba at 9:44:20 instead of  9:44:40.

It is stated in an official statement that the crew had not sufficiently checked the departure time and had performed the departure.

Bloomberg reported that there were no official customer complaints filed about the early departure, but if there any customer who had not caught the train, had to wait for the next one-four minutes.

According to BBC, it is rare for trains in Japan to be off-schedule.

Source: http://wgntv.com/2017/11/18/japanese-rail-company-sincerely-apologizes-after-train-leaves-20-seconds-early/