Hand painted Nippon Tea Set

I think this is a complete set of egg shell porcelain dishes. There are six saucer and cup settings, a sugar bowl w/ lid, a cream dish, and a tea pot w/ lid. The only damage that I can see is one saucer has a chip in the brown trim and one cup has speckeled paint on the inside of the cup. The paint might be original though since it is the same blue as the beads of paint around the brown trim. When held up to the light, you can see objects placed behind the saucers and teacups. They are translucent. Truthfully, I would like to know more about the time period of the set and if it is worth anything or better to keep as a family heirloom. Thank you.