High school student
Nanako is a beautiful teenage girl with chin-length brown hair that is split on both sides, brown eyes and full pink lips.
She is mostly seen in her school uniform.
Initially, Nanako was a judgmental person like when she saw Makoto Sunakawa, she fell in love with his good looks while quickly judging Takeo Gouda, who was Rinko Yamato's (Nanako's friend) boyfriend as a giant gorilla and not at all cool like how she described him. She even talked bad about him behind Rinko's back. However, after Takeo saved her from a fire, she quickly changed her opinion of him, realizing what a good person he is and has stated she likes Takeo as a person. However, she seems to be getting less judgmental as she has taken interest in Osamu Kurihara, whose appearance didn't initially attract her and with whom she was initially annoyed with and agreed to date him, quickly becoming happy and lovey-dovey with him. She appears to be easily annoyed, as shown when she was grossed out by Osamu's comment about her having nice legs. She is also rather impatient at times and can be stubborn and hard headed. She has even described herself as someone who is not cute, can't bake, is not honest about her feelings, and can be hard to get along with. She can be somewhat insecure, as shown when she repeatedly waited for a sign that Osamu liked her but he kept remaining oblivious and was upset when he didn't save her from some scary men and instead called Takeo for help. However, after he proves how much he cares for her and asks her out, she accepts and has become very happy and lovey-dovey. She also seemed somewhat jealous of how happy Rinko was with Takeo as she believed she couldn't receive that much happiness but after getting into a relationship with Osamu and going farther with him than Rinko had with Takeo (she kissed Osamu but Takeo and Rinko who have been dating longer haven't even done that), she acted comically superior to Rinko, stating she would give her advice and seemed to enjoy it (though not maliciously). She is supportive of her friends, as she came up with an excuse about why Rinko didn't come home late to her parents so Rinko could be alone with Takeo and could be nosy in their relationship.
Nanako is usually seen hanging out with Yamato and her friends as they all attend Koizumi Girls' Academy.
Osamu is Nanako's boyfriend as of volume 5.
- The name Nanako means "vegetables, greens" (菜) (na) and "child" (子) (ko).
- Nanako's surname Yamazaki means "mountain, hill" (山) (yama) and "cape, peninsula" (崎) (saki/zaki).
- Out of all of Rinko Yamato's friends, Nanako seems to stand out the most from the group as having the most individualistic personality, while the others tend to react and talk more in a group and are yet to be seen with individual personalities.