Mystery Jugendstihl-Style Vase

I got this vase off ebay. it was listed as Awaji, which it clearly wasn't, but was still very interesting. I think it's beautiful - w/ very unusual glazes. The inside is sky blue - and the bottom is sort of that color too. the main color is cobalt blue, w/ salmon/peach, ochre, and bright green tones. the photos don't do it justice, unfortunately. there appears to be a number stamped in ochre on the bottom - i think it's a 20. any info appreciated!