In the summer of 1985, 9-year-old Ken Miyajima took an airplane alone from Tokyo to Osaka. He packed his backpack with snacks and juice and was excited about meeting his cousins and visiting Japan's high school baseball mecca, Koshien Stadium.

Ken's life ended that day, when the Japan Airlines jumbo jet crashed into mountains northwest of Tokyo in what remains the world's deadliest single aircraft disaster. But today his story still resonates with children and adults, who see it as teaching the value of life.

Kuniko Miyajima, 71, began speaking at elementary and junior high schools from 2016 about her son Ken and how she has lived through the deep sorrow of losing him, in her latest effort to pass down the memories of the accident.

Leading an association of relatives of the 520 victims of the 1985 crash, Miyajima has also held lectures on safety and victim assistance issues for government and company officials involved in the transportation business.

But for a long time, it was too painful for her to share Ken's story with others, especially with children around his age.

"Speaking about the memories of Ken would just have made me cry," Miyajima, who had instead used essays and other writing to express her personal emotions, said on the eve of the 33rd anniversary of the crash. "It was only after about 30 years (from the accident) that I thought I may talk about Ken to children."

Her feelings about Ken, her second son who was in the third grade of elementary school, have been a mixture of love, sorrow and regret.

On Aug. 12, 1985, the day of Flight 123's accident, Miyajima saw Ken off at Haneda airport in Tokyo. Ken was fascinated with trains and planes, and the trip was a reward from his parents for swimming 25 meters in a pool for the first time.

Less than an hour after takeoff, the Boeing 747 crashed into a mountain that came to be called the Osutaka Ridge in Gunma Prefecture, killing all but four of the 524 passengers and crew members aboard.

(Kuniko Miyajima, 71, winds up a music box at the grave marker of her son Ken at the Osutaka Ridge in Gunma Prefecture on July 21)

Despite a desperate search, only Ken's right hand and fragments of his body were returned to the family.

Miyajima blamed herself every day for letting Ken fly alone. She shed tears of grief at mealtimes and thought living on without him was more painful than dying itself.

But she began picking up the pieces of her broken heart, gradually coming to believe that her son was not alone in death.

A phone call from the mother of a 22-year-old woman who was seated next to Ken in the plane eased her pain. She told Miyajima about two months after the accident, "My daughter was a sweet girl. She loved children. She must have been holding Ken's hand tight."

During the classes for children, Miyajima speaks about how meaningful their lives are to family and friends, just as in the case of Ken.

Although the grief of losing a loved one never goes away, it can be turned into "energy" to help prevent future tragedies.

Miyajima says taking up issues like "death" and "accidents" in a straightforward manner is usually not seen in school education in Japan, but children seem to get the message.

Miyajima said one student wrote, "I want to live as long as I can, for the sake of Ken."

Although Miyajima has spoken about Ken in a program for children, its powerful message has also touched their parents, who had a chance to listen to the same lecture repeated for adults.

Among them is Mikiko Ishihara, 41, who first heard Miyajima speak in June last year at an elementary school in Tokyo attended by her son -- though her own past is linked to Ken's from her schooldays.

Ishihara was Ken's classmate in the third grade, although she never imagined she would have any role to play in keeping the memories of the calamity alive.

She had thought of Ken when she frequently went to Koshien Stadium as a young girl and when media reported the anniversary of the accident each year, yet it was no more than that.

But listening to Miyajima's lecture changed her way of thinking. "I now think I should do something for my friend Ken, who must have wanted to live more," Ishihara said.

Ishihara is now assisting Miyajima's activities, including tours to the Osutaka Ridge organized for children and parents. In July, her son Shugo joined the tour while Ishihara was involved as staff.

It may have been a bit too early for her 7-year-old to understand the significance of climbing the 1,565-meter mountain, studded with hundreds of grave markers.

Still, Ishihara hoped that visiting the site and praying together for a boy of around the same age of Shugo became a memorable experience for her son.

While Miyajima is emboldened every year to reach out to the younger generation, she is aware of a "gift" she is receiving from children who ascend the steep trail with her.

"Children who go to the mountain talk to me about Ken as if he is their friend, alive in front of them...That moment makes me so happy," she said.

Making notes about episodes from Ken's life that she plans to read in class still brings tears to her eyes. But she does not want to be framed simply as "a mother who is shedding tears due to the sorrow of losing her child," she said.

"I tell myself not to sob in front of children. What is more important for me is that they feel something from my talks...and see what comes out from that (for a better future)," she said.

Miyajima believes speaking about Ken and delivering his messages are the homework her son has left for her to fulfill throughout life.

"Some people say I might have been living a different life if the accident did not happen. But to me, there is no other life than this and I will walk through it, together with Ken."