Windcutter

Flora (The Organization's previous Number 8) was the first one showing this technique. After the seven-year time skip, Clare (The Organization's previous Number 47), in memory of Flora, was shown to have mastered Flora's Windcutter, utilizing it effectively during her battle with the awakened being Agatha.

Usage
It is a lightning-fast slash that requires the user to draw, swing and re-sheath his/her sword all in the blink of an eye. It is shown to be very accurate and does not use up any Yoki, allowing the user to perform it continuously without tiring and with a minimal number of unnecessary movements.

Quick Sword and Windcutter
After the first skirmish in The War of The North, Flora challenged Clare to a quick duel in order to test her Windcutter against the latter's Quick Sword. After the duel, it was determined that Flora's Windcutter was slower, but more precise than Clare's Quick Sword. After the confrontation, Flora surrendered the title of "fastest sword" to Clare.

However, it should be noted that the Windcutter can actually be considered superior to the Quicksword. Since it requires no Yoki, it is more difficult to sense, especially if the user suppresses his/her Yoki and even though it is slower, the slashes are still so fast that they are nearly impossible to follow with the naked eye, making it much faster when you take into account the proportion of speed compared to Yoki release. On the other hand, the Quicksword requires controlled awakening of the sword arm to achieve that sort of speed and therefore, is a much more dangerous technique to use and can also be sensed. Also, since the Windcutter is more accurate, the user has substantially more control over his/her swings, reducing the amount of energy expended due to unnecessary movements. However, the Windcutter wasn't enough to defeat Rafaela, who could easily deflect every swing, and Clare had to resort to the Quicksword, calling this technique the "greater" one.