In the game, the katana is found in the Headmaster's Office locked in a case, with an explanation for that in the Headmaster's Tapes. YandereDev once stated that the katana could be something that the headmaster confiscated but never got rid of.
The katana cannot be concealed in the player's inventory and is seen as suspicious. As such, if any student sees Ayano Aishi holding the katana, her reputation will be damaged by ten points at high School Atmosphere.
Ayano cannot use a katana when fighting a Heroic student and will automatically lose, as the weapon is too unwieldy to use in close quarters.
There are 4 killing animations for the katana, depending on Ayano's level of sanity. The katana animations were shown in the video "Should Yandere Simulator be re-named?"
- High Sanity: A diagonal slash through the student's stomach.
- Medium Sanity: Two diagonal slashes through the student's stomach.
- Low Sanity: She knocks the student down to the ground and repeatedly stabs them from above.
- Stealth Kill: She covers the student's mouth and stabs them from behind.
- As of the March 5th, 2016 Build, a mind slave cannot be given a katana.
- Before the March 15th, 2016 Build, the katana killing animation was stabbing a student in the neck. It was not held over the shoulder either.
- Ayano holds the katana the same way as she holds the axe, baseball bat, the magical girl wand, and the shovel.
- The katana killing animation is the same as the fantasy sword, the knife blade, and the sword.
- As of the June 21st, 2016 Build, there is a placeholder sound effect for the katana.
- YandereDev plans to make the katana a one-of-a-kind item, so when it breaks, it stays broken.
- Kocho confiscated it from a delinquent in 1988.
|“||Is that a...katana? That better be a prop or something...||”|
— A student seeing Ayano holding a katana.