There are so much we can find information about youth movement in the early 1900s until it leads to WWII. Most of them are ultranationalist movement. The trace of youth and student movement in Japan, however, seem to lost after WWII.
It's peculiar I haven't found anything much in details (except Anpo treaty protest) about Japan's youth movement in the 1960s-1980s, especially considering other countries experienced a very vibrant youth movement in those decades (maybe I just haven't searched enough). It piques my interest that LA Times reports that student protest has finally returned in Japan, in the event of the recent war bill legislation.
So... how was Japan's youth movement since WWII? Book or article recommendation is also greatly appreciated. Thanks!
Maybe I can shed some more light on the leftist student movement in Japan during the 1960s. I can't really say much about the other decades or other movements with my limited library here.
In general you can say that the beginnings of the Japanese student movement were in September 1948 when SCAP allowed the formation of the zengakuren (全学連), a student union very close to the JCP. During the 1950s this organisation differentiated itself into two main branches. The Yoyogi (JCP loyal) and the Anti-Yoyogi (basically they were not fond of the JCP's main doctrines and were themselves split into several smaller branches). From 1959 onwards they rallied together with labor unions to fight against the Anpo which culminated in the occupation of the parliament on the 20th of May 1960 and the resignation of Prime Minister Kishi Nobusuke in July of the same year.
In 1965 a new cause was found and the zengakuren once again allied with labour unions and the traditional left to oppose the American intervention in Vietnam as well as several other issues. The Haneda and Sasebo incidents of 1967 and 1968 are probably the most representative of the new radicalisation. Another example of the range of the student protests is the occupation of the Tōdai from February 1968 to January 1969. You have to imagine that the most prestigious university in Japan was completely inoperative for almost one whole year and wasn't able to resume classes until the students were forcefully expelled in a street war like scenario by police forces including barricades and molotov cocktails. This is a video of the assault on the last stronghold of the students.
In late 1969, finally, the Japanese Red Army (sekigunha) formed that tried to carry the revolutionary flame on with even more radical ideas. But except for the hijacking of a plane in March 1970 they didn't 'accomplish' very much and were soon lost in infighting and incompetence.
During the same time, of course, there were nationalist student groups as well. At times even fighting side by side with the police against the left.
Hope I could help you some, or give you some nods in the right direction.