This is a Japanese Imari ware porcelain plate, known for its distinctive, richly patterned design in underglaze blue, iron red, and gold enamels. 

Imari ware is a style of Arita porcelain made for export from the port of Imari in Japan, popular in the West from the late 17th century through the Meiji period. 

The elaborate and vibrant designs were often inspired by Japanese textiles and were highly sought after by European potteries, which produced their own imitations. The gold in the design was functional as well as decorative, as it would have reflected light beautifully in homes lit by candlelight or gas light. 

Most Imari pieces are unmarked, but their style is highly recognisable. 

The seal is a four-character mark, which is a common feature on some pieces, though many Imari items are unmarked.