The cogged lap joint is a stronger variant of the half lap joint. What makes it stronger is less removal of material from the bottom piece, so it’s not weakened like in a half lap in which half of the beam is removed. It’s used often in Japanese temple construction to secure purlins onto rafters. The additional shoulders also add strength against racking and twisting compared to the half lap version.

You can see a video of me making this joint with hand tools here.