If you only have a short trip to Japan but want an easy day trip from Tokyo, Yokohoma can be a good choice. It is easily accessible from Tokyo by train and has a very different feel. Yokohoma is a port city. While I hate traveling around Japan on a Sunday because it is so crowded, the lively port at Yokohoma makes the crowds bearable. There is always something going on and on a beautiful spring day in less than a mile we saw an outdoor market, an African tourism festival, a flower festival, and a kid’s boat race.
The cup of noodle museum is right down town and fun way to spend some time. The two highlights were making our own cup of noodles (the line may look insane but it moved pretty quickly) and the movie which tells you about this unique invention.
But skip lunch at the noodle museum and walk to China Town which is lined with both crowds and restaurants.
I also love the Raumen museum in Yokohoma and have now been a couple of times.
As I said, Yokohoma is not a must do stop in Japan. But if limited to public transportation and the Tokyo area, then it is worth considering as a day trip.