The straight katana is a straight blade, a single-edged sword.
Chokutō in Japan was mainly produced before the 9th century; its basic style and forging techniques originated in ancient China during the Han Dynasty.
Another straight blade sword called ninjatō is known as the ninja's weapon, usually 60 cm or less in length.
Ninjas often dressed as peasants during their travels to evade interrogations of border guards. Therefore, the so-called ninja hidden weapons are usually adapted from farming tools and gardener props.
Most of these weapons were invented and forged by themselves, and only they knew how to use them, so those weapons looked like ordinary daily necessities to others. This is one of the main reasons why ninja weapons are lost nowadays.
There are seven ninjutsu weapons that modern people usually know from various ninjutsu secret books: Syuriken, Makibisi, Sinobigatana, Hukiya, Sikomidue, Tek Koukagi, Mizugumo.