"They are not only my patients, my kids — but also my life-long wards," said Li Shenghe, a 71-year-old doctor on Dalu Island, Dandong city in Liaoning province.

Since graduation in 1969, Li has spent his whole life on Dalu Island, taking care of more than 900 families.

The 6.6-square-kilometer Dalu Island, located at the mouth of Yalu River, is the largest island in the far north of China's coastline. The island's population is about 3,000.

From April to November, it takes almost one hour for the ferry to reach the island. But from December to March, the sea ice isolates the island and poses the biggest challenge for Li, when he has to face all kinds of emergencies by himself.

Li still remembers a postpartum hemorrhage case decades ago when he worked over 10 hours to save the mother and child.

Because of limited resources, he taught himself Chinese medicine and traveled all over the island to collect herbs before the 1980s.

In order to improve his medical skills, he studied hard and qualified as a doctor in 1980. After that, it took him another 10 years to qualify as a chief physician in 1989 when he was 41 years old.