Chika Itoh is a main character in the series Strawberry Marshmallow. She is the younger sister of Nobue Itoh and lives with her in what becomes a central gathering place for the group. Chika is twelve years old and in the sixth grade, sharing a classroom with her next-door neighbor and best friend, Miu Matsuoka. Her date of birth is May 11th, she has brown eyes, and her short hair is typically styled with a small ponytail tied on one side. She is often seen wearing shorts and tank tops, preferring pants over skirts in her daily life.

In terms of personality, Chika is characterized by her calm, mature, and practical nature. She is frequently described as the most ordinary and sensible member of the cast, possessing a strong grasp of common sense that often contrasts with the more eccentric behavior of her friends and sister. Her older sister Nobue once famously noted that Chika's defining trait is a complete lack of distinguishing traits. This seeming ordinariness, however, is central to her role as the straight man of the group. She is an excellent and sharp-witted tsukkomi, providing verbal and physical reactions to the antics of others, especially Miu and Nobue. Her criticisms can be surprisingly blunt and harsh, sometimes slipping into a rough dialect like Kansai-ben. Despite her composed exterior, Miu's puns and gags can sometimes overwhelm her, leaving her breathless with laughter while her friends watch in confusion.

Chika's primary motivations stem from her desire for a normal, orderly life, which is constantly challenged by the chaotic people around her. She diligently focuses on her studies and is a high-achieving student, which leads to Miu frequently asking to copy her homework, a request Chika always refuses. She is also careful with her money, saving her allowance and locking it in her desk drawer, though her sister often tries to borrow it to buy cigarettes. Miu playfully calls her a cheapskate for not buying treats on the way home from school. Chika's role in the story is to act as the grounded anchor for the series' lighthearted and often absurd daily adventures. She is the lens of normalcy through which the audience views the humor of the other characters, and without her reactions, the comedy would lose much of its impact.

Her key relationships are defined by her roles as a caretaker and a foil. As Nobue's younger sister, Chika is paradoxically the more responsible one, often nagging her older sister or enduring her antics. Her dynamic with Miu is the most significant. They are childhood friends whose windows face each other, separated only by the eaves of their homes, which Miu often crosses to visit. While Miu is the primary source of chaos, Chika is uniquely attuned to her rhythm, capable of keeping up with her rapid-fire jokes and even occasionally participating in her schemes, though Miu usually ends up as the sole victim. They share a deep, almost telepathic默契, and are often depicted wearing matching red and blue outfits.

Regarding development, Chika is a largely static character who grows in her competence and confidence. While she remains the responsible core, her skills as a cook and her ability to deliver devastating comebacks become more pronounced over time. Her patience, though tested to its limits, remains one of her most defining traits. Chika's notable abilities are extensive and centered on domestic life. She is an exceptional cook and baker, far surpassing anyone else in the series. Her specialties range from simple cookies to elaborate decorated cakes and seasonal fruit tarts. She enjoys listening to CDs, reading music magazines, and studying new recipes from convenience stores. She also owns a dog named Satake.