Larry Barrett
Most important trick is to not look too closely. The important shoulders on the face are defined with a knife line, a groove for the saw is then defined with shallow chisel cuts to the knife line. The shoulder is then slightly undercut with a saw. The teeth of the saw do not touch the surface. Unseen shoulders are sawn to ensure they will not interfere with the face shoulder. This is 17th C joinery, a la Follansbee and Alexander.