Chiaki Matsushita

Appearance
Chiaki is a teenage girl of average height with long brown hair that has bangs swept to the right, and blue eyes. She was called cute by Satsuki Shinohara.

Personality
Chiaki's personality is not explored in depth but from what is gathered throughout the Light Novel, she has a quiet, older sister type of personality. She is generally kind to all the boys and girls alike, but she does not actively go out to make friends.

Background
According to her, she was born and raised in a moderately wealthy family, and she was brought up in a kind and free environment. She would achieve outstanding results in school and in return her parents would get her whatever she desired.

Plot
Chiaki has a feeble presence in the Light Novels. She was first seen in Volume 1, talking with Kikyō Kushida and some other girls. According to Kiyotaka Ayanokōji, she and Nene Mori always hung around Kei Karuizawa.

In the Cruise Ship Special Test, she was placed in the Cow group, along with Airi Sakura, Ken Sudō, and Kanji Ike from Class 1-D. The exam ended for her group on Day 3, with an unknown traitor from Class 1-C guessing the VIP wrong.

She was seen walking together with Satsuki Shinohara and Maya Satō, her classmates and friends from Class 1-D, on the 23rd of December. They were talking about how they had not managed to get themselves a boyfriend before Christmas, and Chiaki asked Satsuki if she had a boy in mind, which was replied with a statement that the boys in their class were "catastrophic", and that the best boy had already been "stolen" by Kei-Yōsuke Hirata. Chiaki says that it would be better for them to go out with a senior rather than someone in their year, since all the boys in their year were very immature, but Satsuki replies that she would prefer to date an older student than her. They were just going to talk about Maya's relation with Kiyotaka, when they got out of earshot range.

During the Event Selection Exam, Chiaki was chosen by Kiyotaka, the commander, to participate in the Flash Mental Arithmetic event proposed by Class-A, along with Rokusuke Kōenji, and had her wear the commander intervention headset. According to Kiyotaka, she had answered every question correctly till the sixth one, after which she was barely able to keep up with the numbers being projected, and was unable to answer correctly. The difficulty level of the questions was termed "impossible" by even Chie Hoshinomiya, Class-B homeroom teacher. After the tenth question had been displayed, Chiaki, along with the other participants, save for Rokusuke, had not even managed to pick up their pens before it finished. Kiyotaka provided her with the correct answer to the question-7619, using the commander's intervention, and she wrote it down. Even though she gave the event her all, Chiaki lost to Kōhei Katsuragi, who had correctly answered 8 out of the ten questions.

Later, in her monologue, she states that she had started to pay close attention to Kiyotaka after the end of year special exam, but she was not romantically interested in him. According to her, she was probably among the top 10% of students in their year, but had not revealed her abilities since she did not want people to be jealous of her. She had thought that even if she tried her best, the chance of Class-D being able to rank up the classes was minimal. However, after closely observing Kiyotaka, she had arrived at the conclusion that Class-D might be able to reach the higher classes if both she and Kiyotaka tried and used their complete abilities. By observing Kei's behavior in class, she was able to deduce that she was attracted to Kiyotaka, and the only logical solution to this change of liking from Hirata to Kiyotaka would be that Kiyotaka was actually very gifted.

She later met up with Satō and Shinohara at 11 o' clock and brought up the topic of Shinohara's relationship with Kanji Ike. When Shinohara tried to reject any such involvement of her with Ike, Chiaki used Satō to egg her on and tell them more, resulting in Satsuki finally opening up about her affiliation with him. After discussing a bit more about Chiaki's likings in boys, she brings the topic of Kiyotaka and Satō's relationship, but drops it immediately afterwards, understanding from Satō's look that he had probably rejected her. They move to a café, where Satō reveals that she had already confessed to Kiyotaka, causing Shinohara and Chiaki to almost spit out the tea they had been drinking. She further says that she had been rejected, confirming Chiaki's deductions. Chiaki observed that since there wasn't any strand of anxiety or wavering in her words, it meant Satō had probably confessed during the winter break itself, which was correct. When Satō said that she thought Kiyotaka liked Kei and that Kei also probably liked him, Chiaki was able to guess that that was probably the truth, since she had been closely observing Kiyotaka and his actions, lately. She was also able to almost guess the truth behind Arisu Sakayanagi's choice of saving Kiyotaka in The Class Poll special exam, which was to face off against someone "unexpected", but dropped the thought. She sees Kiyotaka's figure outside the café, and excuses herself on the pretext of making a call, to follow him.

Pretending to be on her phone, she kept her eye on Kiyotaka while walking in his direction. Calculating the distance she would have to keep to be unnoticed by him, she was just about to greet him when the acting director, Tsukishiro, approached him and they started talking. Chiaki found it weird that their conversation was taking a long time, even more than ten minutes. She decided to follow him for a bit more, unaware of the fact that both Tsukishiro and Kiyotaka had already detected her presence. She was ambushed by Kiyotaka when she turned around the corner where Kiyotaka had gone to, after his talk with Tsukishiro, causing her to jump in surprise. She did not even try to act clueless to his question of why she had been following him, knowing that would make no difference. She tried to attack Kiyotaka by asking him questions, but he was able to stop her and asked her questions instead, causing her to reveal that she had seen him talking to Tsukishiro. She finally revealed the reason why she had been following him-which was regarding the answer he had given her as the commander in the Event Selection special exam's Flash Arithmetic Event, which had been exactly the same as what Rokusuke Kōenji had answered. When Kiyotaka anticipated this and tried to explain that he had earlier participated in similar competitions in his Junior High, she interrupted him and said that his skills were at a national level, not just "decent".

Abilities
Chiaki believed from early on in the first year that Class D had no hopes of ever reaching Class A and thus resigned herself to a carefree school life, never putting in any real effort into her academics. She considers herself to be a major underachiever, believing that she could easily score in the top 10% of her class if she truly tried to, but believed it to be pointless as long as she was in Class D. Later on in the light novels, she starts seeing improvements in the class and becomes willing to start contributing to the class. She is also known to be skilled at mental arithmetic and can calculate quickly. She even held her own against Kōhei Katsuragi from Class A in the Mental Arithmetic event in the Event Selection Exam.

Name Etymology

 * The name Chiaki  consists of kanjis that mean "thousand" (千) (chi) and "autumn" (秋) (aki).
 * Chiaki's surname Matsushita  consists of kanjis that mean "pine tree, fir tree" (松) (matsu) and "under, below" (下) (shita).

Trivia

 * As Class D is for those with flaws, Chiaki's flaw is her distant behavior.
 * For the 2nd Year arc, when asked about her aspirations for the next year, she answered 'Just like how I’ve been doing it until now. Playing with friends, putting just enough effort into studying. But that depends on the situation. I'll do what I have to do I guess.'