Thank you for submitting your item for appraisal. This appears to be a late 20th century chinese Shiwan ware 石灣窯 vase, with dark blue glaze and decorated with a prunus branch in bloom in relief. The sign at the base is most likely just a sign used by worker in the kiln who gets paid per item. It might be the surname "Shi" 時.
The estimate is based on similar items offered or sold at auction. There is no measurement for the sentimental value you might attach to the item.