For very many years (since the early 70’s) I built furniture, that I still have and use, with a Stanley No4 as my one and only plane – and only one blade for it. I still have, and use, that same plane. I now have other planes, but the first one is still my ‘go to’ plane. I have just given away my set of chisels, to my son, as I have collected a few old wooden handled ones which I now prefer, but those old blue plastic Marples set did me well for about 25 years.
I agree, that’s a nice and easy set up to start with. I’d say a block plane it’s handy for small areas, and touch ups. A no.5 is excellent but a bit heavy and tiring sometimes. I find that a nice rabbet block plane (shoulder + block) with two irons with different sharpening angles it’s essential to me. One fine flat rasp and a medium flat file would complete my set.

To start off you only need either a 1/4-inch or 3/8-inch mortise chisel (or some size close to those). I prefer 3/8-inch. You don’t need a whole set of mortise chisels. Mortise chisels (also spelled “mortice chisels”) are used for chopping mortises (rectangular holes) into the side of your board to accept the insertion of a tenon. “Mortise and Tenon” is a very common and very strong joint that most people have heard of.

A marking knife is used for marking where you will be cutting with your saws and chisels. For getting into tight spots (like dovetails) and making very accurate lines (which is vital for tight fitting joints) you need just the right marking knife. You would think that any old knife would work, but you would be wrong. Years ago I purchased several that didn’t work well.
“Basic,” on the other hand, is a word that allows for growth – and that’s exactly what you want in your woodworking tool kit. You want to be able to take the same kit with you through many years in the craft. With my basic woodworking tools list, I wanted to provide a core set of tools that will serve you well from project to project. I’m especially concerned these days with the transition to hardwood furniture making, as opposed to plywood boxes of various sizes. That’s the transition I’m making right now in my own work!