TOKYO (Kyodo) -- In the three northeastern Japan prefectures hardest hit by last year's massive March 11 earthquake and tsunami, 1,580 children lost one or both parents, according to a survey of the three prefectures at the end of last year.

According to the Ministry of Health, Labor and Welfare, a majority of these children are being taken care of by their relatives.

Sora Sasaki, 7, from Yamada, Iwate Prefecture, is one such child who lost a parent in the Great East Japan Earthquake and now lives with relatives.

His mother Kanako, 33, was swept away by the massive tsunami in the neighboring town of Otsuchi in the prefecture after the quake struck off the coast of northeastern Japan on the afternoon of March 11, 2011.

Kanako, a single mother, had driven to Otsuchi for her job as an insurance sales agent, leaving Sora at home with her mother Etsuko, 60, and father Masao, 61, in Yamada.

Kanako had been living with her parents in her hometown after getting divorced and returning to Iwate from the town in Saitama Prefecture where she had lived and worked. Sora was then 3 years old and she had raised him since by working in the insurance business.

On March 11, just past 3 p.m., minutes after the tsunami warning siren was activated in Otsuchi, Etsuko's mobile phone rang. Call logs show the call was from Kanako but the connection went dead before Etsuko could answer.

"I wonder what she wanted to say in those final seconds," Etsuko said. "Could it be, 'Mother, I'm scared'?"

Etsuko's husband, Masao, said, "If you had heard her voice, you would have been frantic ever since because you weren't able to save her. It was good that you couldn't get to the phone sooner."

"Kanako must have felt so cold after being engulfed by the tsunami," Etsuko said. As for Etsuko herself, she couldn't take a bath for a while because the idea of soaking in water frightened her.

"Sora lost his mother and we lost our daughter, and it is just too much to bear," Etsuko said. "But we were a bit hesitant about feeling despondent or being interviewed when some people lost as many as four or five family members."

Kanako was listed missing in Otsuchi, after the gigantic tsunami flattened homes, gutted apartment buildings and knocked over trees and tombstones.

In the days immediately following March 11, Sora repeatedly asked his grandparents, "Where's mom?" But after one week passed, he murmured, "Mom must have been swallowed by the tsunami because she doesn't come home even after I've waited this long," according to his grandparents.

That night, Etsuko told her grandson as he lay in bed with his back to her, "Sora, grandma and grandpa, too, don't know where your mom is." Etsuko recalls that Sora didn't move an inch and says it was as if his back was frozen.

"Grandma is sad, too, so you don't need to hold it all by yourself," she told him. It was then he cried out, "I hate tsunami" -- the first time he had expressed his emotions since the disaster.

The car Kanako was driving was later found in Otsuchi. Sora was taken in late March to see it. Sora just stared silently at the overturned vehicle, which was resting on a pile of debris.

Kanako's body was subsequently found and her ashes were delivered to Sora in late September.

His grandmother says she cannot forget the day. "He just looked confused by the urn, as it was something he had never seen before. But it was Sora who said he wanted to see his mom.

"After I put a bone on the palm of his hands, he just touched it gently and said, 'Welcome home, mom. I hope you will rest well.' He didn't cry," Etsuko said.

In late November, Sora and his grandparents are sitting down to dinner. The boy draws laughter by mimicking his teachers at school and actors in TV dramas. "It's always like this at our place," Grandpa Masao said.

After dinner, Sora stood up and went to wash his dishes in the sink. "He does it without being told," Etsuko said with a smile. Etsuko fell in late October and broke her left wrist, making it difficult to do all her chores.

When he went to bed, Sora said good night to his mother, whose photo adorns the family altar.

Sora is now in the first grade at primary school. Masao, 61, continues to work as a roofer, although he had hoped to retire at 60. "After all, I feel responsible," he said. Masao will be over 70 by the time Sora finishes high school.

Tasked with home making and child rearing, Etsuko said she sometimes feels uneasy about her health but is determined to take care of the child her daughter has left behind. "Perhaps it's naive to expect a child to grow up happily after losing a parent," Etsuko said.

"I'm sure that as a boy he will face some hard times and go through a rebellious phase," Etsuko said. "But along with Sora, we also have to grow."