The Mita festival was today and I spent the whole day here. There was even a Hula performance. Mita-sai is the Keio school festival where clubs create booths or events and show it off to the general public.
Get a train card installed on your phone ASAP. This is way more convenient than pulling out your wallet everytime and adding money is way easier. Don't pack too many shirts/shorts. Japan is cold in th