"The background is neither pure white, nor pure blue, but a blend of both, and resembles an ink-wash painting — that is what truly defines blue calico printing and dyeing," Wang says as he explains the distinctive, subtle beauty of the craft, which has occupied a spot in the media limelight since influential content creator Li Ziqi visited him in 2018 to learn his secrets.

After she posted a video demonstration in 2020, online searches spiked on social media platforms like Douyin and Sina Weibo.

When Li came to see Wang again in March, she was excited to discover that his sons and grandchildren have also turned their hand to the craft, and spoke about how some of the dyed products Wang showed her were more fashionable, and in line with the taste of young people.

The Chinese use of indigo, a dye made from bluegrass, can be traced back to the Spring and Autumn and Warring States periods (770-221 BC), when the philosopher Xunzi spoke about watching green bluegrass dye turning from yellow to green, from green to blue, and finally to cyan.