Shinsuke Takasaki's son Sota is too young to understand that his mother might still be alive if 18 hospitals had not denied her treatment when she complained of headaches during labour.
The question of how this could happen still baffles his father, as well as medical experts in Japan, one of the world's richest countries which has long been proud of its high standard of universal health care.
The case of Mika Takasaki, who was 32 when she died, is one of many that has shaken the medical system and led to warnings that emergency wards are nearing collapse.
She was hours away from giving birth at a hospital in the family's western home prefecture of Nara in August 2006 when she complained of a severe headache and then lost consciousness.
Her doctor tried to transfer her to a better equipped facility -- but 18 hospitals turned her down, either saying they were full or that doctors were too busy.
Six hours after she passed out, Mika Takasaki was admitted to a hospital in neighbouring Osaka prefecture, by which time she was in a coma with a brain hemorrhage.
"She received surgery and a Cesarean-section," her bereaved 26-year-old husband, a security guard, told AFP as Sota romped around the house.
"The baby was born, but she passed away eight days later. She never regained consciousness. She probably didn't know her child was born. She never saw him."
A string of similar cases have made headlines in recent months.
In October a 36-year-old woman in labour also died of a brain hemorrhage after being turned away by seven Tokyo hospitals.
A 69-year-old cyclist injured in a road accident in Osaka died in February after 14 hospitals refused to accept him.
On April 4, a 65-year-old man died from heart failure after seven hospitals rejected him in Miyazaki prefecture.
These cases, although among the most shocking, are not isolated, officials said.
Last year ambulances or medical centres had to make four or more calls to get hospital beds for severely injured or ill patients in 3.6 percent of cases, or for 14,732 people, said the Fire and Disaster Management Agency.
Experts say people are being failed by the system because of a complex mix of economic, demographic, professional and legal factors.
The number of emergency patients in Japan has surged by 20 percent over the past decade, due partly to the rapid aging of population, said emergency medicine expert Shuji Shimazaki.
Japan's health expenses have ballooned to 33.13 trillion yen (340 billion dollars) in the year to March 2008, nearly double the cost of 20 years ago.
The government sets the fees that both public and private hospitals can charge their patients.
The trend has driven out of business many so-called level two hospitals that treat common injuries -- and shifted the burden to level three hospitals, which offer emergency care for critical patients.
To guarantee income, many hospitals try to keep all beds occupied, leaving little room for when emergencies arrive, said Yasufumi Itani, deputy director of Kanagawa Children's Medical Centre near Tokyo.
Patients are also to blame for over-crowding emergency wards with minor injuries and ailments, said Itani.
"There is an illusion that medical care comes cheap," he said. "People want to go to the emergency room of a big hospital even for slight injuries, causing a congestion of patients there."
As the government has tried to slash public health costs, many doctors have failed to earn what they deserve, said Shimazaki of the emergency centre of Tokyo's private Kyorin University Hospital.
The allowance for working overnight has long been around 10,000 yen (100 dollars), he said -- about seven dollars per hour and less than a convenience store worker may earn.
Work hours are gruelling -- it is not unusual for doctors to work 36 hours straight. A recent survey showed doctors at 10 emergency centres worked nearly 78 hours a week and had barely two days off a month.
For all their troubles, they face the risk of being prosecuted for malpractice -- which is dealt with under criminal not civil law in Japan.
"You don't want to be sued and end up in prison, or prosecuted for murder, as a result of your hard work," said Itani.
Many young doctors have opted out of the trauma wards after reforms five years ago allowed medical school interns to choose their specialities and locations, and the ensuing exodus has only worsened the squeeze.
Today Japan -- a country of 127 million -- has 2,500 doctors who specialise in emergency care, half the number the government estimates is needed.
Facing a public outcry, the government plans to double spending on emergency care to 20.5 billion yen in fiscal 2009 from last year.
It's high time, said Shimazaki, who warned that the spate of hospital rejections has caused "a strong sense of social insecurity" while the system is now "on the brink of collapse".
Mika Takasaki's father-in-law has campaigned since her death for the establishment of a "fair third-party organisation" that would investigate possible medical malpractice cases.
"Sota doesn't know he has no mother," said Kenji Takasaki.
"But someday he will ask us why there is no mother in the family. When that day comes, I want to tell him that, thanks to his mother, the medical system has improved."