Niigata Prefecture hammered copper chasaji (tea scoops)

These Japanese hammered copper tea scoops are about 3" long x 1.5" at their widest. One bears a Kotobuki label and the other had some adhesive from a missing label before I cleaned it. Both have a stamped maker's mark on back which I have not been able to identify.

I sent an email to Kotobuki to see if they could identify the maker and they replied that they were made in Niigata which is a prefecture where several well known copper makers have studios. Tsubame City is a focal point for copper work there. Gyokusendo, which made a chasaji that I posted earlier, is located in Tsubame City. The link below explains the making of copper pieces in Tsubame City and has links to other foundries. I had already concluded that these two scoops were probably made in Tsubame City, or the vicinity, but Kotobuki generally does not name specific kilns or foundries that make the items they sell. Still researching these marks.

https://kogeijapan.com/locale/en_US/tsubametsuikidoki/

Scoops like this are made by cutting a sheet of copper to size and then laying the sheet in wood mold and using a variety of hammers and other tools to beat them into shape. They are then submersed in a chemical solution which changes them to the desired patina. The hammer marks on this pair are not as pronounced as on the Gyokusendo chasaji that I posted a few months ago, probably because the copper sheet used to make these scoops was much thinner. I ran across some images of the process used to make tea scoops like this but don't immediately find it, now. I will do another search and if I locate it, will post a link to it.

These were part of a tea set I purchased on an on line auction site which consisted of a ceramic teapot and four cups, stainless strainer, common Iwachu trivet which I posted recently and these two scoops. Everything had Kotbuki labels. The teapot and one cup were broken in half due to negligent packing. This was really disappointing as this was going to be a great every day tea set with a very interesting black and yellow accented glaze. I don't think I will try to mend the teapot using Kintsugi as I am not sure that there is any food safe adhesive which will reliably bond something constantly immersed in near boiling water without failing. I had also purchased a new bamboo handle to replace the wire handle on the teapot which did not do it justice. The seller was very good to work with, honest and refunded my entire cost, while allowing me to keep the remainder of the set. They had delegated packing for this item to someone who did not understand how to pack pottery for shipping.