It may never be possible to document San Francisco in its entirety. But if you look through the center of a doughnut, you might glance at the city in microcosm.

“Circle of Donuts,” a documentary short by Tokyo director Toshikazu Hosoki, is scheduled to screen at the Mill Valley Film Festival on Oct. 6, 13 and 16. The 10-minute film profiles Aya Ahn, owner and head chef of Bob’s Donuts. The 11-day fest is also set to feature new releases from heavy hitters like Sofia Coppola and Hayao Miyazaki. 

Hosoki lives in Tokyo, but in 2022, he spent five months visiting a friend in San Francisco’s Nob Hill neighborhood, just blocks from Bob’s Donuts. After a friend introduced him to the shop, he returned nearly every day. On a midnight visit to pick up his favorite doughnut (an old-fashioned), he had a conversation with Ahn. Hosoki was surprised when she greeted him in Japanese, as he said that he’d rarely met a Japanese woman who owned a restaurant, especially as an immigrant. Right away he knew he wanted to make a film about her.

Hosoki got his start as a filmmaker with his 2020 short film “Silent Rider,” which follows a lone skateboarder riding around Tokyo. “Circle of Donuts” is his second film and one of two San Francisco-based documentary films he’s produced. The other forthcoming project, “Developing Our Future,” follows a group of Bay Area teenagers enrolled in a real estate development scholarship program. To varying degrees, he said, his films all touch on the theme of gentrification. 

In “Circle of Donuts,” Hosoki wanted to highlight Bob’s Donuts’ role in the community. Bob’s is the rare sort of San Francisco institution that pulls in tourists and locals alike. The 24-hour Polk Street location catches bar crawlers at 2 a.m., as well as office workers on their way home in the early evenings.

“It’s kind of weird,” Ahn said in an interview in the film. “But even at 3 a.m., our shop is super lively.”

Hosoki’s camera wanders out of the shop between interview snippets and footage of Ahn frosting doughnuts. When it’s dark outside, customers standing in line have agitated conversations, punctuated by laughter. In one clip, the crowd sings “Happy Birthday.” 

Regulars standing outside the store describe Bob’s role in their lives. “As a taxi driver, I would come in here late at night, get a coffee, get a couple donuts,” one man said.

“Sometimes at night, when the bars close, I come here for the munchies donuts,” another said. “And in the mornings, I come for my wake-up donuts.”

Bob’s, as Ahn describes it, is a landing pad for all sorts of San Franciscans at all hours of the day. In the 20-plus years she’s spent behind the counter, she’s had a front-row seat to it all. Some customers buy doughnuts for unhoused people. Others get dropped off in limos. Some arrive immediately after getting married.

“It’s interesting to sometimes see hookers and police standing in line together,” she remarked.

These slices of life intersect at Bob’s, turning the doughnut shop into an informal community center. “While in line, people are not just quietly waiting,” Ahn said. “They’re actually chatty and social.”

“Some even exchange business cards,” she added.

Ahn traveled from Japan to California to study abroad for six months and ended up staying in the state after getting married at the age of 21. By the time she took over Bob’s Donuts from her parents-in-law, she had three children — the oldest of whom was 5 — and no business experience. (These days, her daughter, who went to business school, shares advice with her.)

Despite the challenges, she found a way to make it work. Before she took over, she says, the shop’s lines weren’t that long. Now, Bob’s has three locations.

For Hosoki, Bob’s is a hub of community in an increasingly isolated world.

“What we’re missing is a togetherness …” he said. “This kind of community texture is very important.”