Little Chinese Black Ceramic Teapot / Impressed Mark / Unknown Age

Goodwill was the source of some interesting Asian pieces today. First I found this little 2 cup teapot. It measures 7" from spout to handle and only stands 3 1/2" high. The ceramic is a dense slate black almost like basalt or Wedgewood. There is an impressed mark on the bottom but, I'm not sure if it's Chinese or Japanese. I'll have to check Gotheborg's site. It's in very nice condition with just a few chips on the bottom lip of the lid were it's much thinner. -Mike-