Abstract: A corner joint for a structure formed of stacked timbers, such as a "log" house, and a form of timber for use in the same. The timbers may be tongue-and-groove members milled from wooden stock. The joint structure is formed by two channels which are cut vertically on opposite sides of the timber, with cutout notches being formed through the timber above and below a central tenon. The sidewalls on each vertical channel are curved, one being concave and the other convex. When assembled to form the joint, the convex sidewalls nest within the concave sidewalls so as to form a tight, stable interfit and also eliminate the direct line path which might emit light, air, or water to the interior of the building through the joint.