Vintage, hand-painted fine china by Sone of Japan

Hand-painted gold filigree on Tiffany & Co.-esque mint blue and bright-white fine china. The maker's mark bears no series number, but the pattern is SON42 from the Sone company in Japan (now closed). Bought by my late grandfather for his baby daughter in Tokyo in the early 1950s and handed down to me with my mom's passing. Rare, among the Sone patterns sold at the time. Full service for 12. Each setting covers 3 plates, 2 bowls, 1 teacup & saucer. Servingware includes 2 large platters, 1 soup/vegetable tureen with vented lid, 1 serving bowl, 1 gravy boat, 1 teapot and a cream & sugar service. Minor use over the years but protected, dark storage throughout. No fading or scratches. Only one visible chip, on the edge of the largest platter. One teacup is missing and presumed broken. Hand washed throughout their life so far, to preserve the gold cornucopia- and scrollwork pattern. The pattern is no longer stocked by Replacements.com, but their site has a few details about the series and Sone's overall patterns: https://www.replacements.com/china-sone-son42/c/153025