The bottom of the porcelain IMPERIAL IRONSTONE CHINA should be Japanese royal porcelain imported from China. N.K.PORCELAIN CO This is Japan Maritime Safety Administration Ceramics Production Corporation. It should be imperial porcelain imported by the Japanese royal family from Jingdezhen, China through the Japan Maritime Administration Ceramics Corporation.

The approximate age can only be initially determined to be the Republic of China period, and the value is about 500 yuan.