. 
From what I can gather so far, Nippon Yokohama Imura china is from the late Meiji period, circa 1890 and may have extended through at least the early Taisho (1912-1926).
Varied UK and US sites date Nippon Yokohama Imura Zo anywhere from 1890-1920's. The Japanese sites I have found state this porcelain as mainly Meiji era (1868-1912) but some seems to have been produced in the Taisho period (1912-1926) as well.
See links:
www.tanabetetsuhito-collection.jp
books-jp.com/index.php?route=product/product&product_id=396
https://www.old-noritake-antique.com/item/u0580.htm
https://www.old-noritake-antique.com/item/u1540.html
