chinese very big plate 18inches

[natalina2014]

Hello everybody!
Please help me with authenticity this chinese plate and period.Size  18.3 inches
Thanks for any help , 
Best regards,
Natalina

[peterp]

Hello, what you have is likely a 20th century product. I base my conclusion mainly on its underside, namely:
1. the spotless glaze of the bottom
2. the color decoration underneath the rim
3. the mark

Mark - the double ring around the mark is too even. With antiques I would expect a slight different in darkness or breadth of stroke at the end or beginning of either ring.
Color decoration under the rim - I would not expect this before the late Qing dynasty (about early 20th century)
Glaze of bottom - it is just too spotless for an antique

The mark is a Yongzheng reign mark, but the decoration underneath would be late Qing dynasty at the very least. Such combinations are mostly from later in the 20th century.