Have you been to Yokosuka?
also what places should I visit
I think I've been there once but didn't stay for very long. It's close to Haneda which would be why I visited for a brief moment.
It depends on what you want to see. If you want WWII stuff, Hiroshima and Nagasaki would be the place to go obviously. For anime, stay in Tokyo and go to the anime districts. For the tsunami, check out any town on the north-eastern shore (aka the Tohoku region). Osaka, Tokyo, and Sendai are all pretty cool in general so chilling out there wouldn't be so bad.
Do you own a Samurai sword? :O
I think my family may own one, I am not entirely sure. I don't own one personally though.