Own domain that was recently trademarked in Japan by Sony Network communications

[Sirkarl]

While doing a routine search of results on domains I own. I came across a Japanese site. The site claims trademark of my domain name. Of course before I bought and just a few minutes ago I searched U.S trademark and it is not trademarked here. It indeed is trademarked in Japan but was done after I purchased the dot com domain. My question is, Should I approach Sony Network Communications that trademarked the domain that has an active site and offer it to them or just post it for sale. Another weird thing. I did my whois search and it states that my domain can be purchased for $4500.00 first year and I think it was $9.95 after that?

I do not recall putting it up for sale but I own quite a few and am terrible at keeping track of them all. Thanks everyone!