The process of folding steel during the forging of a katana blade is a characteristic of traditional Japanese swordmaking techniques. While the exact number of times the steel is folded can vary, it is a common belief that a traditional katana blade is folded between 8 to 16 times or even more, depending on the preferences of the swordsmith and the desired outcome.

Folding steel involves repeatedly heating, hammering, and folding the metal layers to remove impurities, homogenize the composition, and enhance the blade's overall strength and flexibility. Each folding cycle helps to refine the steel, eliminate voids or inclusions, and distribute the carbon content more evenly.

The folding process also contributes to the creation of distinctive grain patterns on the blade, known as hada, which can be visually appealing and unique to each katana. The layered appearance of the blade is a result of the repeated folding and forge welding of different steel layers.

It's important to note that while folding steel is a traditional technique used in the creation of high-quality katana blades, modern swordsmiths may employ alternative methods or variations based on their experience, preferences, or the specific requirements of the blade. The number of folds can vary, and some skilled swordsmiths may achieve desired results with fewer folding cycles while maintaining exceptional quality and performance.