Dia Kurosawa

Dia Kurosawa (黒澤ダイヤ, Kurosawa Daia; born 1 January 2000) is a Japanese school idol and student administrator associated with Uranohoshi Girls’ High School in Uchiura, Numazu, Shizuoka Prefecture. She served as president of the school’s student council and became a member of Aqours, the school idol group formed during the campaign to prevent Uranohoshi’s closure. Her administrative position, previous experience with school-idol activities, and knowledge of the national school-idol system influenced the group’s institutional development.

Kurosawa is the elder daughter of the locally prominent Kurosawa family and the older sister of Ruby Kurosawa. Although her formal manner and emphasis on regulations initially created distance between her and the emerging idol club, she possessed extensive knowledge of idol performance and followed the activities of μ's. Her early opposition to the club reflected her assessment of its organization and preparation rather than opposition to school idols as a category.

Early school-idol activity

Before the formation of Aqours, Kurosawa attempted to establish a school idol group with Kanan Matsuura and Mari Ohara. The project ended after interpersonal conflict developed around an overseas performance opportunity. Matsuura concealed her concern about Ohara’s injured ankle by presenting the group’s withdrawal as a unilateral decision, while Kurosawa understood the underlying circumstances but did not resolve the resulting disagreement. Ohara subsequently left Japan to study abroad, and the three students remained estranged until their final year at Uranohoshi.

This unsuccessful project shaped Kurosawa’s later evaluation of the club organized by Chika Takami. Kurosawa required the new group to demonstrate sustained commitment before receiving formal recognition from the student council. Takami and Riko Sakurauchi developed the group’s initial performance program under these conditions, while Kurosawa monitored its compliance with school rules and its ability to attract an audience.

Formation of Aqours

The idol club emerged in response to declining enrollment and the proposed consolidation of Uranohoshi. You Watanabe participated in its initial activities as a performer and contributed to the preparation of stage costumes, placing her work within the group’s ordinary division of performance and production responsibilities. The club’s early public appearances established the organizational basis from which Aqours later developed.

Kurosawa joined after the circumstances surrounding her earlier group with Matsuura and Ohara were disclosed and addressed. Their reconciliation integrated three experienced third-year students into the newer organization. Ruby Kurosawa and Hanamaru Kunikida entered as first-year members whose participation widened the club beyond the students responsible for its initial establishment. Yoshiko Tsushima subsequently joined and incorporated her established theatrical persona into the group’s stage presentation.

The resulting nine-member structure combined students from all three school years. Kurosawa’s membership did not end her student-council responsibilities; instead, she occupied both administrative and performance roles during the campaign concerning Uranohoshi’s future. This dual position enabled her to connect the club’s activities with decisions involving school facilities, public events, and recruitment efforts.

Organizational role

Within Aqours, Kurosawa maintained a highly formal conception of rehearsal and performance. Her knowledge of established idol groups informed her attention to synchronized movement, audience expectations, and competition requirements. These practices were incorporated into collective rehearsals rather than administered through a separate office, and artistic decisions remained distributed among the members.

Kurosawa also participated in AZALEA, an internal unit consisting of herself, Matsuura, and Kunikida. The unit provided a smaller performance configuration within Aqours and developed material distinct from the group’s full-member repertoire. Its composition joined one member from each school year, reproducing the wider organization’s cross-year structure on a reduced scale.

Her public demeanor emphasized linguistic formality and observance of institutional conventions. In private settings, this behavior coexisted with detailed enthusiasm for school-idol culture and occasional sensitivity concerning the disclosure of personal interests. The contrast affected her relationships with other members but did not constitute a separate public identity.

Uranohoshi closure campaign

Aqours used performances and participation in Love Live! to increase attention toward Uranohoshi and its enrollment campaign. Kurosawa’s student-council office connected this effort to the school’s administrative response, although the group did not obtain enough prospective applications to prevent consolidation. The closure decision therefore remained in effect despite the visibility generated by the club.

Following that outcome, Aqours reframed its competition entry around the preservation of Uranohoshi’s institutional memory. Kurosawa participated in the group’s subsequent national performance and in the final activities held at the school. Her graduation concluded her formal service as student-council president, while Aqours continued as an association among its members rather than solely as a club dependent upon Uranohoshi’s continued operation.

Characterization and public representation

Kurosawa is commonly represented with long black hair, red eyes, and a red-associated performance color. Her speech includes the emphatic expression “buu-buu desu wa,” which functions as a recognizable indication of disapproval. The expression contrasts with her otherwise controlled register and became recurrent in representations of Aqours’ internal interactions.

Her given name is written with the katakana characters ダイヤ, corresponding to “diamond.” Ruby Kurosawa’s given name follows the same gemstone convention, linking the sisters through family naming practice. This relationship is also reflected in their differing social behavior: Dia generally assumes an instructive role, while Ruby’s development as a performer increasingly reduces her dependence on her elder sister.