Thanks to all who replied to my question about the Navy of Sweden.

For those who are curious, Sweden does indeed have a Navy, but they don't
have anything in their fleet the size of an aircraft carrier (of whatever
type). Consensus is that it is unlikely they'd pay a port call in Japan, or
even stray too far from the home water-Baltic region, unless they were
visiting for some special purpose or event.

Web sites to check for more information include the Jane's site
(http://www.janes.com) and the Swedish armed force homepage
(http://www.mil.se/FM/index_e.html)