As you know Japane New Era name has decided on 1st of April and it will be "Reiwa" ”令和”. which will start from 1 st of May.
Due to this change, we will have long long Golden Week starting from 27th to 6th of May.
Normal Golden week is 4days or 5days, However, as the rule in Japan, a day between national holiday turn to be a National holiday.
Therefore, this Golden week in 2019, Normal National holiday is 29thof April(showanohi), 3rd of May, 4th of May(Green day) and 5th of May(Child day).
However by changing 30th of April and 1st of May to National holiday, a day 2nd of May between 1st of May and 3rd of May turn to be a holiday.