Vintage Japanese Modern Ikebana Stoneware Gray Signed Small Quality Vase EUC

Vintage Japanese Modern Ikebana Stoneware Gray Signed Small Quality Vase EUC 5.5" x 5.5" x 1.5"  In the center, you can add water & there are metal spikes built in to hold onto the stems you're placing in the vase & help them stand upwards.  The metal spikes have a bit of dust/lint in it that I haven’t tried to remove. This has weight to it & is a very high quality Japanese-made vase.  I cannot decipher the potter's marking.  Dark gray glaze that almost looks black.