Most of Japanese kitchen knife manufacturers a burned tang into a handle and then hammer the end of a handle. Inside of a handle burns by a heated tang, then resin comes out of the wood. It provides as adhesive function so that it won’t come off easily. However, it can cause tempering or cracking handle, furthermore, it is hard to take the tang out once it attached. It is difficult to attach properly.
A recommended way for beginners are to make a hole as a shape of a tang, and then attach a tang with adhesives. As Japanese kitchen knives are popular all over the world, it is generally used wax or bond instead of resin to attach it.
*Sample movie attach a tang to a wa handle