One man has launched an inspirational quest to find the relatives of those who fell in the service of their country. A month ago, a letter was delivered to a post office in Nanjing, capital of Jiangsu province. Nothing unusual in that. But what was strange, and deeply touching, was the story behind the letter.

It was addressed to martyr Wang Weihua. On the envelope was written "Wang Weihua (20 years old) who died in December 1947 at the Heze battle. Request the postman to try one more time to help the martyr find his home".

This is the sixth year the letter has been mailed. This time, postmen requested police help. After double checking their archives, including the history of the address and the martyr's family tree, the police believe the name of the martyr should be Wang Dianhua, not Wang Weihua.

Investigations are ongoing. But the letter itself is part of a wider search. It is one of the nearly 1,000 letters mailed by Zhang Jingxian during the past decade to find the relatives of martyrs who died in 1947.

The 54-year-old has been sending the letters twice a year.

"These letters were mailed to more than 10 provinces, including Guizhou, Shanxi, Zhejiang and Guangdong, but 99 percent of those letters were returned because the address couldn't be located. I keep sending them out again and again. As long as I persevere, there will be hope," Zhang said.

Zhang has been greatly encouraged as five families who may be relatives of those who fell have called him this year to confirm explicit information.

"There are also some postmen who keep the letters for further research," he said.

Zhang has been Party secretary of the Zhanghe Zhuang community of Dianhu Tun, Heze in East China's Shandong province, since 2007.

A soldier from 1982 to 1986, Zhang holds the martyrs in deep respect. Every day he lingers for a while at the Zhanghezhuang martyrs' cemetery where 176 soldiers are buried, of which 57 tombstones bear the inscription "Unknown Martyr". The cemetery commemorates soldiers who sacrificed their lives during the Heze battle which took place in December 1947 during the civil war (1946-1949).

Built in 1948, the cemetery is also an education base for people to learn about history and the revolutionary spirit. Every Tomb Sweeping Day, residents, including students and government officials, come to the cemetery to pay tribute to the martyrs.

"In 2008, when people came to sweep the tombs, somebody said these martyrs have been at the cemetery for several decades, but we have no idea where their family members are," Zhang said.

"When I was a soldier, I missed home and my family members missed me. I frequently wrote home. I guess family members of the martyrs also want to know where they are buried."

He spent six years finding out information about the martyrs, including which army these soldiers belonged to. He visited old soldiers and military museums.

"To date, I've found the names of 96 martyrs, and I have addresses for 57," he said.

Zhang started writing letters in 2013.

"I was surprised when I got a letter to a martyr - Gong Jianhou in 2015," said Wang Dejian, the postman at Tanbu town in Linyi, Shandong.

Wang returned it as he couldn't find the address on the letter. In 2016, Wang got another letter for the same martyr. This time, he suddenly realized the village name on the envelope could be another village with a similar name. After visiting several families and checking information, Wang finally delivered the letter to the martyr's nephew.