I am not sure of this vase's date, I can only GUESS it is "mid - late 20th Ccntury". The mark says Yongzheng Nian Zhi ( Yongzheng period made ).
Thank you for sending me pictures of this vase. I would like to publish it since I find it a good example of the high quality pieces that have been made during the 20th century and in time also will be valuable "antiques".
In Chinese porcelain, "age" is always an issue but that should not allow us to forget "quality". Generally speaking, a common rock is very old. If someone have made a dent in it, it might be an "artifact" - very old but it would take a real enthusiast to think of that as an object of art.
A commonly neglected fact in considering the later Chinese porcelain was that in 1916 there were a serious attempt to reinstate a new emperor in China (Hongxian 1916). The preparations had been going on for years and included deciding on - and actually ordering - new imperial porcelain based on an enameled early Qing dynasty style.
Taking into account the turmoil in China at this time, the available facts seems to support that as much as 1,4 million Yuan seems to have been spent on making 40 000 new Imperial pieces. All left over material after this was used by the Jingdezhen potters in the further process of making high quality porcelain with diverse marks - one of them four characters Yongzheng marks. To indicate the later period, the corners of the surrounding square seems to have been made cut off like the one illustrated.
Now, I am not suggesting that this vase is a (Hongxian 1916) period piece, the shape seems to elaborate to fit with an early Qing dynasty style. I have just taken this opportunity to dwell on the merits of some 20th century porcelain.
While studying the picture please note that the borders are hand painted while later and simpler pieces have some kind of transfer printed borders.
A likely date for this piece seems to me around the 1950's, based mainly on the Eurasian influenced style of its shape.