The style of decoration on this bowl is known as dip and run. The rim has been dipped into paint and then turned over to dry, causing drips to run down the side on the interior and exterior.
From Gournia, Crete
Richter, Gisela M. A., Grace Crowfoot, and Donald Benjamin Harden. 1956. "Part I: Ceramics from c. 700 B.C. to the Fall of the Roman Empire." A History of Technology: The Mediterranean Civilizations and the Middle Ages, c. 700 B.C. to c. A.D. 1500, Vol. 2, Charles Singer, Eric John Holmyard, Alfred Rupert Hall, and Trevor Williams, eds. p. 263, fig. 239, Oxford: Clarendon Press.