Kenji Kawano is perhaps best known for his photographs of the Navajo code talkers recruited by the Marines to communicate military orders in their own language in World War II, baffling the Japanese. Around 400 young men, who had never been away from the reservation, served in some of the bloodiest battles in the South Pacific and are credited with helping win the battle of Iwo Jima.

As a Japanese native, and thus a “former enemy,” Mr. Kawano might have seemed an unlikely candidate to tell the code talkers’ story. But his background is what helped him bond with the Navajo veterans who had remained silent for so many years. Soon after he had settled into the Navajo Nation in 1974 to work on a project, he was struggling to learn the language.

While he was hitchhiking in 1975, a big camera bag on his shoulder, he was given a ride by Carl N. Gorman, one of the original 29 code talkers. Mr. Gorman invited him to a Navajo Code Talkers Association meeting, and Mr. Kawano began to photograph them at functions and parades. He quickly realized they were the same age as his father, who served in the Japanese Navy during the war and trained as a human torpedo for a potential suicide mission.

“My father said the war ended early so he could come home,” Mr. Kawano recalled. “That’s why I was born and I came to America, taking pictures of the former enemy. He came to see me back in the ’90s; he met Mr. Gorman, and I have a picture of the two of them. So life is very interesting.”

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Those images are among four decades of work included in a two-part retrospective, “40 Years With the Navajo,” which will be exhibited through Jan. 30, 2016, at the Navajo Nation Museum in Window Rock, Ariz. The second part of the exhibit opens today.

Mr. Kawano had been a graphic designer in Tokyo before moving to Los Angeles to become a professional photographer. An antiques dealer on Hollywood Boulevard told him about the Navajo Nation, the biggest tribe in the United States. Having grown up watching westerns, he was intrigued. He took a bus to Gallup, N.M., and found a place to live with a Navajo family on the reservation. Speaking neither English nor Navajo, he used hand gestures to communicate.

Still, he felt at ease there and thought that the Navajo people, especially the children, looked Japanese. Not at all what he had seen in the movies. Sometimes people asked if he was Navajo.

Mr. Kawano worked part-time jobs as a gas station attendant, a janitor and school photographer at what was then known as the College of Ganado, while learning Navajo phrases, studying English and always taking pictures. He met his wife Ruth, who is Navajo, while she was a student at the university. He started to run into military veterans who had been stationed in Japan. Some sought him out to practice the Japanese they had learned many years before.

After his fateful encounter with Mr. Gorman, Mr. Kawano went on to work as a staff photographer for the Navajo Times, and was made the official photographer for the Navajo Code Talkers Association and, later, an honorary member.

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He undertook a book project of portraits and interviews and spent two years driving across the vast reservation’s expanse, often on unmarked, unpaved roads, to visit the veterans at home. He would leave his cameras in the car at first, sensitive to culture and customs. Then he would ask if he could photograph and interview them for the project. For most, it was the first time they had spoken publicly about their wartime experiences and the first time many family members heard what their loved ones had gone through.

“Warriors, Navajo Code Talkers” was published in 1990 with a foreword by Mr. Gorman, who described the book as “a tribute to symbolize the healing of the wounds of war” and thanked “Kenji Kawano, my Japanese-Navajo friend.”

Mr. Kawano credits his wife for her support and his acceptance in the Navajo community. “People say this photographer’s wife is Navajo, one of us,” he said. Mrs. Kawano said that her husband’s sincerity shines through in his photographs. “I think meeting someone that is so different and being the person that Kenji is, very giving and caring, I think they saw that,” she said. “He was there to listen and no one had ever done that before.”

The Kawanos travel widely, but their home is still in Window Rock, the capital of the Navajo Nation. He has exhibited across the United States and in Japan.

Mr. Kawano continues to work on several projects on the reservation. He is loyal to his favorite film, classic Kodak Tri-X black and white, and is now shooting more with a Hasselblad. He processes each roll, one at a time and prints exquisite silver gelatin fiber prints in his home darkroom.

“In black and white, the tones make it really beautiful,” he said. “I love the beauty of black and white. When people shoot in digital they go by convenience. I think it’s important to do what I actually do, what I love. But of course I have a fear of how long I can use film; until then I’d like to keep it always in black and white and print whole negatives.”

But what remains closest to his heart are the code talkers. Some of his most poignant photographs are recent portraits of the aging warriors.

“I met more than one hundred code talkers. When I was taking pictures in the ’70s, ’80s, people didn’t take pictures of the code talkers; they were just people who went to war. For me they are special, they did something special during World War II, and I wanted to document.”

Now many of them are gone. Chester Nez, the last surviving member of the original 29, died last year at age 93.

“It’s hard to see them getting old; everybody using crutches, wheelchair, that’s happening,” Mr. Kawano said. “But I always appreciate that they share their experience with me. And every opportunity I have, I go to see them and keep taking pictures – until the last code talker.”

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