The lower course of the Yellow River (Huang Jiang) has varied dramatically in historical times. During the second millennium BC the lower course ran almost northwards. In the next two millennia it swung around little by little like the hands of a clock until, from 1289 to 1324, it was flowing in a southeasterly direction into the center reaches of the Huai River which in turn emptied into the lower Yangzi. Since 1324 it has moved back and forth in an irregular fashion, and at present again debouches north of the Shangdong peninsula. The primary cause of these rapid shifts has been the heavy load of silt carried by the Yellow River. As the current slackens near the sea, much of this is redeposited, building up the riverbed and sooner or later forcing the water to run elsewhere.