Thank you for submitting your item to Mearto for appraisal. It is an elegant japanese ceramic, so called Awata Yaki 粟田焼 and signed Kinkozan 錦光山.
The typical Chawan tea cup shape is decorated with a thick blue enamel glaze covering the outside in a kelp like pattern. The Kinkozan family of potters were active from the second half of the 17th to the first quarter of the 20th century. I would date this piece to the early 20th century, made for the japanese market and not for export. The estimate is based on Kinkozan items of similar size and age offered or sold at auction. I hope the information provided was helpful to you.