The folding process for katana blades, like other traditional Japanese swords, varied depending on the swordsmith and the specific requirements of the blade. It is important to note that the number of folds does not necessarily determine the quality or performance of a katana. The folding process was primarily used to refine the steel and create distinct grain patterns, rather than to increase strength or durability.

Historically, Japanese swordsmiths typically folded the steel between 8 to 16 times during the forging process. However, some exceptional blades may have undergone more folding, reaching 32 folds or even higher. It is unlikely that katana blades were folded excessively beyond practicality, as excessive folding can potentially introduce impurities or weaken the steel.

The focus in forging a katana lies not solely in the number of folds, but in the overall craftsmanship and attention to detail throughout the entire sword-making process. Factors such as the choice of steel, heat treatment, differential hardening, blade geometry, and the skill of the swordsmith have a more significant impact on the final quality, strength, and performance of a katana.

Modern swordsmiths may choose to incorporate folding techniques as a nod to tradition or for artistic purposes, even if the practical benefits are minimal. Ultimately, the quality of a katana is determined by a combination of factors, and the folding process is just one element within the broader context of the sword's construction and craftsmanship.