Bisento is a really big sword that was used a long time ago by some people in Japan. Imagine a big stick with a sharp blade at the end, kind of like a big, long triangle. People who used bisento were usually really strong and skilled fighters. They would swing the bisento around with both of their hands and use it to cut and slice through things like armor, shields, and other swords. It was a very dangerous weapon and not something that just anyone could use. Nowadays, bisento is mostly used in martial arts to learn how to fight like the skilled warriors of the past.