Let me answer you correctly:

1. What you call a saber is actually a samurai sword, because in ancient Japan only samurai could wear striped swords, that is, samurai swords.

2. The wavy stripes you mentioned are produced during the production process of the samurai sword

The specifics are as follows:

The samurai sword, due to the craftsmanship It is mature and its manufacturing process and technology are very exquisite. During the casting process of the sword itself, in order to ensure the sharpness and flexibility of the samurai sword, some special ingredients (such as a certain proportion of low-carbon elements) and special manufacturing processes (such as clips) are added Steel process), which changes the composition of the katana itself, so when it undergoes the quenching process, the blade will form a striped pattern. And this pattern cannot be changed artificially.

3. As for the statement above that "it is purely for decoration and will be added after completion."

This is a misunderstanding. In fact, every hand-made samurai sword will have Stripes, but the craftsmanship of the katana doesn't end when the stripes appear. There are also subsequent processing, such as polishing. Polished. There is also a kaifeng, as well as a matching hilt and scabbard.

In the polishing process, the Japanese spirit of pursuing perfection is reflected. In addition to the polishing and polishing of the knife itself, the stripes on the blade also need to be processed through a confidential process to ensure its perfection. Reflect the noble style of the samurai. It also makes the katana even more perfect.

Here are also some interesting information for you to refer to:

1. The production process of samurai swords is entirely handmade, and not everyone can get this honor casually. The large number of Japanese samurai swords that appeared in World War II were essentially forged and mass-produced in military factories and used in wars of aggression. There would be no stripes on these swords.

2. Samurai swords are still produced by master swordsmiths in Japan. The process of polishing and processing the stripes alone takes three months. It has to be appraised by several Japanese master swordsmiths. It is considered completed, otherwise it is a waste product

3. Only the United States can produce the whetstone used for sharpening, and the price will not be less than hundreds of thousands of dollars.

If you are interested, you can watch the documentary "Legend of the Samurai Sword"

I hope my answer can answer your questions!