The number of times a samurai sword, such as a katana, is traditionally folded during the forging process can vary, and there is no fixed number or rule governing the exact number of folds. The act of folding the steel during the forging process is primarily done to homogenize the material, remove impurities, and create a fine-grained structure within the blade.

In traditional Japanese swordsmithing, the steel used for the blade is typically folded multiple times. The folding process involves heating the steel, hammering it, and then folding it over itself before repeating the process. Each fold doubles the number of layers in the steel, creating a layered or "grain-like" pattern known as hada.

The number of folds can vary, and it is influenced by factors such as the skill and preference of the swordsmith, the desired aesthetic effect, and the quality of the steel being used. It is not uncommon for a katana blade to have hundreds or even thousands of layers resulting from the folding process.

It's important to note that the number of folds alone does not determine the quality or performance of a katana. Other factors such as the choice of steel, the skill of the swordsmith, the heat treatment, and the overall craftsmanship of the sword play significant roles in determining its quality and performance. The folding process is just one step in the complex and intricate process of creating a well-crafted and functional katana.