In 1942, when Yoshito Wayne Osaki was forced into an American concentration camp along with some 120,000 persons of Japanese descent, he and his family could take only what they could carry. For Osaki, this meant leaving behind his prized possession and best friend: his dog Teny.

As his family set off for the camp, Teny ran after their truck for as long as he could keep up. Osaki could only watch, tears filling his eyes; it was the last time he ever saw his pet.

More than 60 years passed, and Osaki, who became a prominent architect, never talked about the pain he felt leaving Teny behind.

Osaki’s story is now being widely shared, in the form of a children’s book called “My Dog Teny.” Its official launch party will be held on Sunday, Aug. 22, at the Japanese Cultural and Community Center of Northern California (JCCCNC) in San Francisco’s Japantown.

“This story is such a simple way to explain the pain, frustration and uncertainties people felt, in a very powerful way,” said Paul Osaki, Yoshito Osaki’s son and the executive director of the JCCCNC. “It’s not a happy book, but I hope it’s an educational book.”

In 2000, the elder Osaki joined a writing class for former inmates that was held at the JCCCNC, and composed an essay on the theme of “loss.” The story of his separation from Teny was originally published in 2001, in an anthology titled “From Our Side of the Fence.”

“Of the stories in our book, this has been one of the most popular among students and all audiences,” Brian Komei Dempster, a professor at the University of San Francisco who taught the writing class, said via e-mail. “It touches a vein in all of us and forces us to confront these questions: If you were told to leave your home, what would you take, what and who would you have to leave behind, and how would you face that?”

Though expressing his feelings on paper was initially difficult for his father, Paul said, he watched him rewrite and revise repeatedly, finding catharsis in crafting his tale. Since the anthology’s publication, Paul said, countless community members have remarked what a good children’s book it would make.

With a grant from the California Civil Liberties Public Education Program, Paul undertook the adaptation process, which has not been without challenges. Since originally writing the tale, Yoshito Osaki has suffered loss of hearing and the onset of dementia. Though his father “has good days and bad days,” Paul said, he endeavored to involve Yoshito in every step of the process.

With Yoshito’s input, Paul developed a more optimistic ending to the tale, going through more than 30 drafts. Instead of the original ending, which stops at the heartbreaking moment of separation, the book ends with the true story of Yoshito Osaki’s eventual adoption of another small tan pup, which he, of course, names Teny. Yoshito Osaki also consulted with Felicia Hoshino, the book’s illustrator, reviewing her sketches of his childhood home and his beloved dog.

Hoshino’s illustrations, created through a complex process involving layers of paint, ink, tissue paper and sepia wash, capture the narrative’s time period, as well as its deep emotions, which struck a chord for Hoshino.

“It was a shared experience that perhaps my grandparents had to go through,” Hoshino said.

A fellow community member who knew the Osaki family growing up, Hoshino said she was touched by the story and “jumped at the chance to be involved.”

Hoshino acknowledged that the tale might be sad for children, but added, “nonetheless, I think it’s good to expose them to the internment experience, and this might be a good way, through pictures.”

Dempster expressed a similar sentiment. “It is a heartbreaking piece, because rather than browbeat us over the head with its message, it shows us in a tender, human way, with clear and rich detail, the devastating consequences of the forced removal of Japanese Americans from their homes and into camps,” he said in an e-mail.

Paul Osaki and Felicia Hoshino will speak at the book release party, and “My Dog Teny” will be read by three of the author’s grandchildren. Yoshito Osaki also plans to attend the event.

Paul Osaki said he is happy that his father has been able to share this story, which he hopes will provide an emotional connection to the Japanese American incarceration experience that will lead to greater knowledge.

“My ultimate hope is that readers will want to learn more about what happened and why,” Paul said. “In reality, there are all these stories that need to be told. They aren’t necessarily stories that would go in a typical history book, but they are an important part of history.”