The burly man delicately places his right elbow on the arm of the chair but the pain hasn't gone away.
As a police officer who has worked in Beijing for almost 25 years, he has suffered his share of injuries in clashes with culprits; this one, though, was the result of an accident during a visit to an undeveloped section of the Great Wall.
"The injuries, the bleeding and the twisted ankles are very common," he said. "We still go on the adventures."
He obviously believes the good work that he and his friends do is worth all the hazards.
A director of an on-campus police station at Peking University, Hong Feng, 44, is better known for his volunteer work towards Great Wall protection. He uses the name Shishu on www.thegreatwall.com.cn a website where he and a group of other equally passionate volunteers share an interest in the ancient structure.
Hong reads extensively about the Wall and posts regularly on the website. But more than that, he and his Internet friends take trips on weekends to less-visited sections of the Great Wall in and around Beijing to inspect sites damaged or collapsed because of inadequate protection.
They face challenges such as getting lost in mountainous terrain at night, the threat of wild animals and accidental wounds. Through it all, their fervour for the culture of the landscape has never dampened.
The Great Wall, built originally as a military structure, holds great significance for the Chinese.
In imperial times, it served as the division between territories, cultures, military forces and different lifestyles. Now it is probably the most widely recognized symbol of the country's spirit.
But apart from a number of sections including Badaling, Simatai and Mutianyu, which have been renovated and are open to visitors much of the Wall is threatened by both natural destruction and lack of maintenance. Graffiti and rubbish are only some of the eyesores hotels and homes are also springing up alongside.
Realizing the increasing dangers to its preservation, insightful and enthusiastic individuals from China and overseas are showing their concern. One place they get together to do that is the website, known as Changcheng Xiaozhan, or the "Little Site of the Great Wall."
The site, founded in 1999, provides stories and pictures related to the Wall. Beyond spurring public education initiatives and protection via networks, photo exhibitions and other modern means, the site encourages research of the Wall and offers a bulletin board for information sharing and discussion.
"It has more than 5,000 registered members," said Zhang Jun, one of its founders. "Among them are entrepreneurs, police officers, professional photographers, college students and members of other organizations involved in historical site protection. Hundreds are as active as Hong."
The website provides a brief introduction in English, and foreigners can participate in the discussion and adventure with the help of members who can communicate in both English and Chinese.
In his e-mail to a website member, Ian Law, a British technical transfer manager from York, called the website "great and very informative." He enquired for information on the glutinous rice that was put into the mortar used to build the Wall during the Ming Dynasty (1368-1644).
Other organizations
Organizations for the Great Wall protection have sprouted up since the mid-1980s. The most influential ones include the China Great Wall Society, which advocates restoring the Great Wall and has established an Academy of the Great Wall to give greater credence to its work. The society is made up of amateur and professional conservationists, architects and archaeologists dedicated to mapping, documenting and conserving the heritage.
Another is the International Friends of the Great Wall, founded in 2001 by William Lindesay of Britain with the support of the Beijing Municipal Administration of Cultural Heritage and UNESCO. It focuses on maintaining Beijing's undeveloped "wild Wall," embarking on public education initiatives and strengthening legal protection.
Distinguished from other organizations, the members of Changcheng Xiaozhan think of themselves as ordinary volunteers or "fans."
"Mr Lindesay has a unique power to direct public attention on Great Wall protection," said Zhang Jun, an electrical engineer. "But what we do is what we really feel from the heart and what we can fulfil. The results can be immediately seen."
Also, the website is unique to use network as the channel to organize adventures and other events. Members never pry to private lives unless they would like to communicate with each other during activities.
"The site's slogan is 'Love the Wall, Love the Life,' " Zhang said. "It's really a home to members who share their interests in the rampart." The group even holds get-togethers and sporting events regularly.
Hong is one of the most dedicated members. He is regarded as an outstanding representative because of his admirable knowledge about the Great Wall and his adventures.
In the past few years, Hong has scanned almost all the major ancient books regarding the Wall. He transcribed the history of ancient dynasties from threadbare books into his computer.
Friends were amazed at his fascination with the voluminous historical records, which were written without pauses or punctuation. Professors say he was the equivalent of a doctoral student of history or archaeology. Some friends call him "the grand academician of Hanlin," referring to the ancient literary academy. He logs onto the site daily and posts an article of about 5,000 words every month.
The volunteer group's exploration combines archaeological investigation, protection efforts and educating nearby residents on how to preserve the parts from which villagers have taken the bricks for many years to construct homes.
"Shishu (Hong) is very persistent in these adventures," Zhang Baotian, a volunteer from the website, said. "We're not doing this for fun but for the truth of history."
During the past several years, he toured almost all the "wild" parts of the Wall in Beijing Municipality and neighbouring Hebei Province, paying some sections more than one visit.
He posted tens of thousands of words expressing his feelings and took more than 15,000 pictures of the mammoth structure and the lives of nearby villagers.
His writings aroused the attention of authorities, which led to repair work on some collapsed sections. Such adventures also help identify the old sections as their dates have been subject to disputes.
In a recent exploration, Hong and another volunteer from the website named Daying ventured to an undeveloped section near Shuitou village in Huailai County, North China's Hebei Province. Part of the structure there was destroyed by the invading Japanese troops during World War II.
One sunny Saturday last August, they set off with an old picture taken by a Japanese that shows swarms of the alien army penetrating the dismantled Wall.
After about two hours of driving, the group reached its destination in the county.
"When I arrive somewhere, I often ask local residents about their ancestry and tales and legends of the area," Hong said. "Enthusiastic villagers could help find the location and offer to lead the way. That helps a lot."
This time was no exception. Led by a local young man, the two trudged for roughly two and a half hours up the mountain to reach a land of briars and thorns.
But to reach the exact site where the old picture was taken, they had to make their way through the thorns, some of which were as thick as a man's arm.
"It could be very difficult to find the location," Hong said. "It may look only one kilometre away, but it could take one day of trekking along zigzagging mountain paths, and you may not recognize the old place even though you may be standing in front of it."
In Shuitou, after almost 70 years, almost no traces of the aggression remained. "It's only a part of the Wall that has been reduced to rubble."
He tried to take pictures of the damaged Wall there; it was hard to hold the camera steady while trying to maintain his balance on a steep slope.
"It was a slope of about 60 or 70 degrees, so it was very hard to stand still," Hong said.
In fact, Hong did slip as he tried to take more pictures. His foot caught some plants below, which prevented him from tumbling farther. But he injured his right elbow when it landed on a rock.
"It still hurts," he said. "Sometimes we've been surprised by snakes and by spiders of colours we'd never seen before and even larger than a pigeon's egg.
"Even bumping into wild birds, which happens frequently in the mountains, has resulted in quite a surprise when they suddenly take off from the jungle."
Other challenges have included a shortage of clean water, freezing temperatures in winter and no mobile phone service in remote areas.
Hong viewed the ordeal in Shuitou as worthwhile, though, because he was happy with the photos he took.
"It's good compared with the old ones," he said.
Volunteers often collect old pictures of the Great Wall, find out where they were taken and try to take pictures at the same location to reflect its current condition in hopes of arousing authorities' attention to the worsening situation.
"I suggest taking pictures here with an unfolded national flag," Hong said later in an online posting, which generated replies from other web members who approved of the idea.
During their explorations, the volunteers always bear a sense of protection in mind, as authorities worry about the threat travellers pose to the already-fragile structure.
They call for travellers to leave nothing but footsteps when they tour historical sites.
Also, they seldom reveal their routes to outsiders for fear that travel agencies and property developers might make use of the information to make money.
"It did happen before," Hong said. "Some travel agencies exploited the section and even used our picture as a selling point."