This album is a comprehensive unit, so in order to figure out the meaning of the song, it should be seen in context of the songs before and after. The previous song left us saying, in so many words, "there must be more to life than dwelling on death." Lovers in Japan responds by saying "Whatever task is appointed to you, see it through. Sometimes even the right seems wrong, but when facing a choice between bad and worse, do your best knowing that there's a light at the end of the tunnel." Since every new day begins when the sun rises over Japan ("the land of the rising sun"), the Osaka sun is poetically referring to the very first moment that the night is ending and the new day is dawning.
This album is a comprehensive unit, so in order to figure out the meaning of the song, it should be seen in context of the songs before and after. The previous song left us saying, in so many words, "there must be more to life than dwelling on death." Lovers in Japan responds by saying "Whatever task is appointed to you, see it through. Sometimes even the right seems wrong, but when facing a choice between bad and worse, do your best knowing that there's a light at the end of the tunnel." Since every new day begins when the sun rises over Japan ("the land of the rising sun"), the Osaka sun is poetically referring to the very first moment that the night is ending and the new day is dawning.