"There is no such thing as 'coincidence' in this world."
"The only thing... is 'hitsuzen'!"
Yuko constantly, if not always, makes references to "hitsuzen" in xxxHOLIC and in TSUBASA RESERVoir CHRoNiCLE. As she quoted from the Kodansha Japanese Desk Dictionary: Second Edition, it is "a naturally foredained event, where other outcomes are impossible." It also has different results for different people. Although hitsuzen can be easily translated as "fate," fate is a destiny brought unto others no matter what they do. In contrast to this, hitsuzen is a destiny that is different for each person that encounters it.

Because of this strong belief in hitsuzen, Yuko states that her meeting with Watanuki is the working of hitsuzen, as well as for Syaoran, Fay and Kurogane in TSUBASA RESERVoir CHRoNiCLE.