Mizuno Yūko (AKA Ms. Kunoichi) is a celebrity athlete, reporter and basketball player who has competed in KUNOICHI and SASUKE several times, and has also been called the "Queen of KUNOICHI" on several occasions, until Miyake Ayako took the title. Mizuno is from Ichinomiya City in Aichi Prefecture.
Her first competiton was KUNOICHI 2, where she was the first to clear stage 1, and the first to reach the final stage in that tournament, where she failed the Balance Walk. In KUNOICHI 3, Mizuno cleared the first 3 stages with ease, and became one of three competitors in the final stage. There, she timed up after reaching the top of the tower 0.12 seconds late (mainly due to her trying to climb up as far as she could instead of reaching for the buzzer in time), with the reporter noting afterwards that if she had one more second on the clock, she would have made it.
Despite failing the final stage in KUNOICHI 3, many people thought that she would become the most likely competitor to complete the final stage. In KUNOICHI 4 however, she shocked everybody when she failed the first obstacle on stage 1, the Buyoishi, which paved the way for Miyake Ayako to become the first ever KUNOICHI champion. Returning in KUNOICHI 5, Mizuno made up for her first stage failure in the previous tournament by clearing stage 1 with ease. She then went on to clear stage 2 as well, but ended up failing Domino Hill on stage 3, an obstacle she had cleared easily in KUNOICHI 3. Afterwards, she then failed stage 1 two more times, falling at the Balance Bridge in KUNOICHI 6, and the Hop Rocket in KUNOICHI 7. She did not compete in KUNOICHI 8, but did compete in KUNOICHI 9.
Mizuno has also competed in SASUKE 6 times. In her first appearance in SASUKE 8, she failed the Godantobi on stage 1. She cleared this obstacle in SASUKE 9, but then failed the Rolling Maruta. She then cleared this obstacle in SASUKE 10 before failing the Jump Hang, after mistiming her jump on the trampoline. She then failed the Rolling Maruta again in SASUKE 11. After missing SASUKE 12, she returned for SASUKE 13, as the third top female competitor, although during her run, she failed the first obstacle on stage 1, the Prism See-Saw. Returning for SASUKE 14, she once again reached the Jump Hang, where she was able to reach the net, but couldn't hold on and ending up failing there. She hasn't competed since.
|2||81||Failed Tenkudou (Final Stage)|
|3||100||Failed Tenkubou (Final Stage)||Reached the top of the tower 0.12 seconds late|
|4||100||Failed Buyoishi (First Stage)||Spring-loaded portion.|
|5||91||Failed Torentta (Third Stage)||Red Zone (33rd Domino)|
|6||Failed Fuandou (First Stage)||Numbers weren't given for the first three stages, so Mizuno's number is unknown|
|7||98||Failed Haso Tobi (First Stage)|
|8||52||Failed Godantobi (First Stage)|
|9||37||Failed Rolling Maruta (First Stage)|
|10||941||Failed Jump Hang (First Stage)|
|11||93||Failed Rolling Maruta (First Stage)|
|13||70||Failed Prism See-Saw (First Stage)|
|14||70||Failed Jump Hang (First Stage)|