The Golden Week is THE national holiday week in Japan, each year between the end of April and the beginning of May. During these days, Japanese people travel in mass by train to enjoy their holidays as tourists.
The next Golden Weeks will take place:
The Golden Week is the longest national holiday for Japanese people. They thus overcrowd trains at two specific moments:
Thus, if you travel outside those peak periods during the Golden Week, trains might be more crowded than usual, but you might not have any problem finding a seat.
It is more or less the same process during the New Year celebration period: usually from December 29 to January 3.
Don’t forget that:
It is impossible to book seats by yourself if you are not in Japan. Moreover, Keikaku does not book train seats.
To avoid any inconvenience if you travel in Japan during the Golden Week, you can choose the JR Pass “Green Car” (First Class) which is always quieter and less crowded.