This lamp is made from a Japanese sake jug from the Meiji or Showa eras (late 19th through mid-20th century). It is a clear glaze with running script kanji.

I have given some links below to similar items that have sold at auction. eBay has many of these kinds of jugs for sale as well, but asking prices on their website can be all over the place, because there isn’t necessarily good background knowledge about pieces. Still, if you search “Japanese Stoneware Sake Jug” there, you can at least get an idea of what some people are expecting to get from them.
I am giving this item a Fair Market Value of $250-$300.

*When selling, make sure the electrical components are functioning, for a higher price.

$120 just vase
https://www.catawiki.com/l/4749527-old-pottery-sake-bottle-adorned-all-round-with-calligraphy-japan-ca-1930-1940-showa-period

$165 just vase
https://www.1stdibs.com/furniture/asian-art-furniture/ceramics/japanese-large-ceramic-vintage-hand-painted-decorated-sake-bottle-jug/id-f_14962431/

$2000 for pair converted into lamps
https://www.1stdibs.com/furniture/lighting/table-lamps/pair-of-antique-sake-jug-lamps/id-f_443585/