Tessen Fans

Tessen Fans were fans used by the Japanese to signal to troops, use as weapons, and deflect arrows with during times of war. Yumi, due to her Japanese descent, uses the fans as her weapons in Lyoko. They are metal ("tessen" is Japanese for "fan of iron") and can slice through most small enemies, or collide with large enemies. They are hard to aim, but fly medium-range. If they miss, they usually come back to her like a boomerang only they have a more complicated flight pattern than most other boomerangs.. Yumi can also use them as an effective shield bloking all lasers barrin the megatank. From the first season to the third season, Yumi stored her fans (Jeremie programmed her a second fan in the second season) below her large yellow ribbon and extracted them when needed; in the fourth season Yumi can make the fans appear and disappear in her hands at will.

In Franz Hopper, XANA, disguised as Franz Hopper, improved Yumi's fans by making them fly longer and lock onto targets. They would also be attracted to monster lasers, making it much easier to use the fan as a shield. Once Team Lyoko found out that XANA was behind the plot, they lost their improved capabilities.