Hidaka was born in Naruse Village (present-day Isehara City), Kanagawa Prefecture, on 27 February 1904. Following her graduation at an all-girls school in Atsugi, she studied nursing at a hospital in Kamakura. Through a friend, she found employment at a Russian perfume company, where she worked as a live-in employee.
In 1923, when Hidaka was 19 years old and working, the Great Kantō Earthquake struck. She described the tremors as being louder and more violent than any noise she had ever experienced. As her workplace collapsed around her, she traversed over rubble to make her way to Yokohama Park, the only evacuation point nearby.
Hidaka was one of tens of thousands of injured people seeking refuge at the muddy, waterlogged park. For three days, she witnessed intense suffering, and decided to take action. She approached the police chief, who sent two constables to assist her in treating the wounded. Using the supplies in her first aid kit, she utilised her former medical training to provide treatment to 68 people.
On her way to Isehara to check on her family, Hidaka’s hopes were she could get more supplies at the local customs office, but it had burnt down. She wrapped a charred rug around her head and continued walking towards her hometown. That night, a farmer and his wife offered to take her in, giving her food, a bath, and a new kimono. The final leg of her journey consisted of avoiding deep crevices in the ground, several wrong turns, and crawling through thick shrubbery; she eventually found that her family were safe.
Word of Hidaka’s heroic actions at the park spread; a newspaper published a story headlined: The Descent of an Angel. Later, she would be publicly commended for her bravery. She wrote a diary of the event at the age of 100, which is still on display to this day in the Yokohama Port Museum, to ensure the tragedy was never forgotten.
Hidaka was married and had children. At the age of 102, she lived independently in her home in Meguro Ward, Tokyo, but would later move into a nearby nursing home.
Hidaka’s age was verified by Japan’s Ministry of Health, Labour, and Welfare (MHLW), and was validated by the GRG with an acceptance date of 7 March 2015.