Katanas are made from steel. Back in the 15th and 16th centuries, when the katana was widely in use, this was the best material. The steel matched with the craftsmanship of the sword-smiths made this weapon much deadlier than a normal sword of the era.
Yes, in ju-jitsu, the katana and occasionally the wakizashi is primarily used.
it depends, often they are made from steel or modern ones stainless steel but there are a few swords used for decoration which are finished or made of silver or even gold.
The sheath is the casing that it is kept in. They can be made of wood, metal or sometimes just leather. If it was made of metal or another hard material it would often be used in battel along side the sword to block attacks. It is also known as a scabbard or in the Japanese Katana's case, a Saya.
In the present wording your question makes no sense. Assuming that you mean something like: 'why did the ancient peoples make metal swords", the answer is that almost until the 21st century, metal was the hardest and most durable metal for any weaponry: much harder than bronze that was used for weapons before metal came into use.
damascus steel
because without his katana(even weilding another person's katana), the samurai is nothing compared to a samurai with his own katana. the katana is specially forged for the particular samurai, and so it is very valuable to their identity.
The Samurai sword is called a katana.
The short answer is no. For starters, if you are referrring to the weapon commonly referred to as the 'Ninja-to', it is a creation of pop-culture and has no precedent in the history of Shinobi. Ninja's did however use Katana's and Wakizashi, which are made from Carbon Steel(literally an alloy of Iron and Carbon, with no other elements). Tungsten is added to some modern swords, but Katana's are generally still made from Carbon Steel, though modern steel can be used, such as L-6.
Cutlery after 'cutlers' who made metal swords and daggers
Bronze, Iron and every other known metal of the time it was used
The Japanese own many thousand of Bokken. Most Bokken are used in training and can resemble in length that of a Katana. It can also be found in various other shapes of swords.
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