Movie
Description
Chiaki Ōgaki is a high school student at Motosu High School and co-founder of the Outdoor Activities Club with Aoi Inuyama. She possesses fair skin, bluish-purple hair usually styled in twin ponytails, and wears semi-rectangular wire-frame glasses. Her camping outfit features black leggings, reddish-brown boots, and a large dark-blue coat; her school uniform follows the standard seifuku design.

Personality-wise, Chiaki is friendly, bright, and playful, radiating high energy. She harbors a mischievous streak, leading her to occasionally play pranks on fellow club members, often targeting Nadeshiko Kagamihara in tandem with Aoi. Her passion for camping stems from childhood family trips, where experiences like eating curry and sleeping outdoors inspired her to establish the club for more frequent adventures.

In the 2022 film, set ten years after high school, Chiaki works for Yamanashi Prefecture's tourism organization after leaving a job in Kyoto. Tasked with regenerating a disused site in Takaori, she travels to Nagoya to meet Rin Shima. During dinner, Rin suggests converting the site into a campsite. Impulsively, and while intoxicated, Chiaki drags Rin to the location via taxi. She also drunk-texts Nadeshiko, Aoi, and Ena Saitō to join them, though only Nadeshiko arrives initially. After a hotpot meal at Nadeshiko's family home, Aoi appears, and Chiaki outlines her campsite development plan.

When Ena later offers help, having missed the meeting, Chiaki assigns roles to all friends. She organizes subsequent meetings at the Yamanashi prefectural building in a room reminiscent of their high school club's cramped space. The group begins clearing vegetation and surveying the site; Nadeshiko and Chiaki later use an excavator and mower to accelerate progress. During a trial camp, Ena's dog Chikuwa discovers ancient earthenware. Chiaki reports this find to her superiors, resulting in the campsite project's suspension after archaeologists confirm the artifacts date to the Jōmon period, designating the area a protected historic site.

Following this setback, Chiaki helps Aoi relocate belongings from a closing elementary school. The two then devise a revised proposal integrating the archaeological site as a camper attraction. Upon presenting this concept via an Ena-directed video, the prefecture approves the plan. The completed Fujikawa Matsubokkuri Camp Base opens on October 2, with Chiaki attending the inauguration.

Trivia notes include her August 31 birthday, namesake origin from Ōgaki city in Gifu Prefecture, and a ranking as the 5th most popular character in a 2021 series survey. Her immediate family remains unseen as of Volume 14. Post-high school, she worked at the Minobu branch of Kawamoto Liquors; the real-life store closed in January 2021.