Dovetails are a traditional way to attach two pieces of wood without the need for fasteners like nails or screws.
Below, John Bullar of the UK presents a short video where he cuts dovetail joints using hand tools. As a professional custom furniture builder, his skill makes the process look very easy. The tools, however, are simple and easily available. A chisel, mallet, and saw are all that are required.
A great trick is revealed early in the video: letting the chisel hang off one board while dragging the other across to mark lines the exact thickness of the board. A precise fit with such old-fashioned tools is remarkable. A contributing factor must be the marking knife, used instead of a pencil to produce the thinnest, straightest lines. Throughout the process, no pieces are measured. They are simply compared to the other side of the joint, and individually shaped for a perfect fit.