Postby Alan » August 2nd, 2006 9:42 pm
Early April before golden week is quite good. The sakura starts flowering in the south in late March and the flower front works it's way up the country during April to the north. The japanese meteorological agency posts a sakura forecast on their website. Quite a lot of people prefer the autumn, which I've yet to experience.
Whatever you do, try to avoid travelling during japanese holidays, in particular golden week. I'm sure it's great if you are already in the right place, but apparently its standing room (if that) on most of the trains in that period.