Kenzan style Black Raku water jar
https://asia.si.edu/object/F1896.45a-b
<p>Clay: dense, coarse, gray. Hand formed. Glaze: mirror-black; inside, thin, grayish. Decoration: in white glaze-relief; crackled. Signatures of Ogata Korin (1658-1716) and Ogata Kenzan (1663-1743)</p>