How did ancient samurai forge their swords?
Ancient samurai did not forge their own swords; they bought them. They were crafted by a special class of people who had developed unique skills, and who sold them to the samurai. If you strike the links provided with this wikified answer, you can read the full story. The process is detailed, but why cut and paste it when it is a simple mouse-click away, and is illustrated with pictures and the odd drawing?