Stainless steel is not typically favored for traditional sword making for several reasons:

1. Hardness and Edge Retention: Stainless steel tends to have lower hardness compared to high-carbon steels used in traditional swords. This means stainless steel blades may not hold a sharp edge as long and may require more frequent sharpening. The lower hardness can impact the cutting performance and durability of the blade.
2. Brittle Nature: Stainless steel blades tend to be more brittle compared to high-carbon steels. This makes them more susceptible to chipping or breaking under heavy impact or stress. Swords require a certain level of flexibility to withstand dynamic cutting motions without fracturing, which is better achieved with other steel types.
3. Difficulty in Heat Treatment: Stainless steel has different heat treatment requirements compared to traditional high-carbon steels used in sword making. Achieving the ideal balance of hardness, flexibility, and other desired characteristics in a stainless steel blade can be more challenging for swordsmiths. Improper heat treatment can result in suboptimal performance or even damage to the blade.
4. Cost and Availability: Stainless steel, particularly high-quality stainless steels suitable for blade applications, can be more expensive and less readily available compared to traditional high-carbon steels used in sword making. This can make stainless steel swords more costly and less accessible for enthusiasts or collectors.

While stainless steel has its advantages, such as corrosion resistance and ease of maintenance, these qualities are less critical in traditional sword making where other factors like hardness, flexibility, and edge retention take precedence. Traditional high-carbon steels, such as tamahagane or specific tool steels, are generally preferred for their ability to deliver the desired cutting performance, durability, and overall authenticity in sword craftsmanship.

It's important to note that there are specialized stainless steels formulated for blade applications, which offer improved hardness and edge retention compared to typical stainless steels. However, even with these specialized alloys, they still may not match the performance and characteristics of traditional high-carbon steels in terms of sword making.