Most mornings, he rises from a twin bed that he shares with his wife and walks a few feet to pull aside drapes covering the windows on the doors facing the street.
Then, the 58-year-old settles onto the concrete stoop fronting his shop and gets to work repairing electronic appliances for his neighbours.
Rent has increased fivefold in the past decade, but Gu still charges customers as little as $6 for each repair.
“It is still affordable here compared to the modern apartments, and the one-story level means … I don’t have to pay additional rent for a separate shop,” Gu told AFP.
Gu’s home is located on the outer edge of a courtyard dwelling with curved tiled rooftops, hundreds of which form networks of “hutong” alleyways in the heart of China’s capital city.
The narrow streets come alive each morning with residents selling breakfast snacks from small stalls — crisp-fried egg crepes, steamed dumplings and warming bowls of millet porridge.
Fruit vendors, butchers and convenience shop owners start their days by setting stools out on the street so they can easily converse with passersby.
They greet each other and gush over children as if they are all family members.
Hundreds of years ago, stately red doors lining the alleys led to spacious courtyards decorated with carved roof beams and painted pillars. Even commoners’ homes featured open spaces in the middle.
But since the mid-twentieth century, especially during the tumultuous Cultural Revolution, many hutong homes were taken from their original owners and eventually bulldozed.
Nowadays, with space scarce in the city of 21.5 million, most hutong courtyards are filled with makeshift wood-panel shacks or higher-quality concrete rooms — allowing each courtyard to accommodate multiple households.
The people who live in each nook may not be kin, but they are very close.
“There is no privacy here, everyone sees your comings and goings and overhears your conversations,” said Luo Pu, a young man living in an alley near the Drum Tower, a historic landmark that was used to keep time during the Qing Dynasty.
“My son, his wife and my grandson live a few courtyards down from ours. We see them every day,” said Wu Xiaoming, a man in his late fifties, who sells homemade cornbread to neighbours in the Beixinqiao hutongs near the neon-drenched “Ghost Street” entertainment district.
In the evening, after fixing a washing machine, Gu loads it onto his small car — really a metal shed on three wheels — to deliver to a neighbour.
Bicycles and motorbikes are the best ways to get around the disorienting alleyways, which can resemble mazes.
Although many of the refined old homes are now rundown, gentrification has begun to transform some of the neighbourhoods into havens for hipsters — with numerous craft breweries and art galleries cropping up.
The changes have made residents optimistic about their neighbourhoods’ future: many surviving hutong have recently been targeted for historic preservation work.
“China changes quickly, but it is often for the better,” Gu said.
“If I keep working hard, we will be fine.”