Seaweed Vases from Japan??

Don't know where these come from? I haven't seen any on the net but I am leaning to Japan. They are beautifully finished with a little line of blue under the green the tallest is 380mm high, the bottom has a concave grinding to remove the pontil. I call them Seaweed vases (although you could say the end looks like the start of an emerging fern frond) as you can see from the last photo I have enough of them to populate a good sized aquarium.