Sun Zhenhong has been trying to revive the fading folk art, known as la yang pian in Chinese, which involves a showman dramatizing stories using pictures inside a box while the audience sees the actions through a series of small holes.

It gained popularity in the northern cities of Beijing and Tianjin in the late Qing Dynasty (1644-1911).

"The shows left an indelible mark on my childhood memory," says Sun, 74, adding that they were popular in the olden days when people lacked other forms of entertainment.

However, the folk art has been gradually replaced by new audiovisual media such as television and cinema.

After retiring as a mechanics teacher at the Tianjin Machinery and Electric Industry School in 2000, Sun immersed himself in recreating the mystery of la yang pian for youngsters. He would rush to the workshop in early mornings when a new idea came to him. With his mechanical skills, Sun successfully made five boxes in different sizes over five years.

He displayed the first box he made at an exhibition hall in the cultural center in Hexi district of Tianjin. It was roughly 2 meters high and had three holes with a convex lens in the middle for people to look inside.

"All the pictures were set into viewing positions by pulling corresponding strings. To ensure pictures do not interfere with each other, a pulley device was installed for precise control," Sun says.

On the upper right corner of the box, he fixed three kinds of percussion instruments, a drum, gong and cymbal, controlled by a rope to make sounds simultaneously.

"Dismantling the old items and recombining components to make a box gives it a sense of nostalgia," Sun says.

The main body of the box was made of a drawer from his old wardrobe. The decorated curtain was selected from an old quilt cover, while the ornamental pattern was taken from an old clock.

Sun has taken his boxes to local temple fairs where he is surrounded by crowds of people.

Chen Hao, 26, a Chinese crosstalk comedian, has been drawn to Sun's shows since he watched one in 2012. He soon started to learn this nearly extinct folk art from Sun. They founded a drama club in 2013, which now has seven members. Sun is responsible for making the boxes, while younger members perform in public avenues in the city.

The drama club has compiled a repertoire featuring Tianjin folk customs, involving characters and plots from Chinese mythology, some elements of Tianjin kuaiban (a form of oral storytelling) and some specially written for children.

In May, the show was listed as one of the representative projects of the intangible cultural heritage of Hexi district in Tianjin.

Cui Yaqian, deputy director with the intangible cultural heritage department of the district, says the shows were a memory of the older generations and a valuable cultural heritage in dire need of protection.

Sun is eager to carry forward the traditional art in innovative ways.

"We intend to present 3D effects with the help of some high-tech elements in the future," he says.