If you want a Japanese sword that is in all aspects traditionally made, you will choose a folded blade. These very high quality swords are handforged in folded high carbon steel.
They are differentially tempered using a traditional method that creates an authentic hamon (temperline). They are equally strong as the monosteel blades, but traditional in every detail.
Kobuse swords are handforged made from folded steel. But instead of using one type of steel, they have 2 different kinds of steel. The inner core and edge is made of harder 1095 carbon steel. The sides and back are made of 1060 carbon steel. This construction gives your Japanese sword even more flexibility to handle the impact of the cut.
They are differentially tempered using a traditional clay method that creates an authentic hamon (temperline). Even in the old Japan, only the highest samurai could afford a laminated (kobuse) blade.