a river in Tomsk Oblast, and, in its upper course, in Krasnoiarsk Krai, RSFSR; a right tributary of the Kiia River of the Ob’ River basin. The Chef is 432 km long and drains an area of 14,300 sq km. It flows along the southeastern edge of the Western Siberian Plain. It is fed primarily by snow, and high water occurs in May. The mean flow rate is 66 cu m per sec. The river freezes over in late October or November, and the ice breaks up in late April or early May. The Chef is used for timber flotation.