They were made by hammering out a layer of steel, then folding it over and hammering it flat again, and then repeating the process several times. Any air caught in the sword would make it brittle and break.
- As "katana" is a Japanese word, the proper transliterated plural is "katana".
- A slightly shorter sword, called the wakizashi, was often used in conjunction with the katana. Other than its length, it had all the same properties.
- Katana have enjoyed growing popularity due to the trend of ninja TV shows and toys.
- Main article: Sword