Hanako Kokubunji, alternately spelled Kokobunji, is the daughter of KOGC Co., Ltd. founder and president Masao Kokubunji, reflecting her affluent family background. She attends Game Middle School as a classmate and close friend of protagonist Fubuki Sakuragasaki, having first encountered Fubuki playing a claw machine outside the ARASHI arcade.

Hanako consistently supports Fubuki in gaming competitions. During the Tokyo BAG Tournament finals, she shouted encouragement about "game spirit," prompting Fubuki to recall the Passion Panties and activate their power to defeat Glass Joe in Crazy Climber. Later, she accompanied Fubuki to Jigokugawara for special training after Fubuki’s loss to Chizuru Jyumonji in the Japan BAG Tournament finals, where they met American gamer Melody Honey and witnessed the Gyulassic Group betray Chizuru.

Her straightforward personality occasionally sparks conflict. She challenged Chizuru to a baseball game in physical education class, losing decisively. Blunt remarks about the dilapidated state of Chizuru’s family-owned arcade provoked Chizuru to expel Hanako and Fubuki while throwing salt at them. Despite this, Hanako showed loyalty by aiding Chizuru when Miss Alka and the Gyulassic Group attacked the arcade, intending to renege on providing the Tranquilizer Gun game and destroy the establishment. After Fubuki narrowly defeated Chizuru in the restarted Japan BAG Tournament finals, Hanako facilitated reconciliation by sending the rare Tranquilizer Gun arcade game to Chizuru, fulfilling her goal to save the family arcade.

Hanako is identified as a teenager without additional distinctive physical traits. Merchandise includes a color version figure released in April 2002 and a November 2002 set depicting her with Fubuki, acknowledging her role. Her appearances are confined to the original OVA episodes and manga.