A statue of Kumarajiva (344-413), a master Buddhist translator, stands at the entrance of the Kizil Cave-Temple Complex in Baicheng county, Xinjiang Uygur autonomous region. [Photo by Fang Aiqing/chinadaily.com.cn]

Artificial intelligence and digital scanning technologies are being used to preserve and restore the ancient murals of the Kizil Cave-Temple Complex in Baicheng county, Xinjiang Uygur autonomous region, according to researchers involved with the project.

The massive complex contains 349 caves, with nearly 4,000 square meters of murals. Carving began around the 3rd century, making Kizil China's earliest large-scale grotto complex.

In Cave 161, dome ceiling paintings in the main chamber have long been obscured by soot. To recover what lies beneath without risking further damage, researchers are applying terahertz time-domain spectroscopy, a noninvasive scanning technique that penetrates the soot and extracts pigment information and linear contours without touching the surface.

Zhao Li, director of Qiuci Academy's institute of digital technology and documentation information, said this marks the first application of such multimodal fusion technology — combining terahertz scanning, X-ray fluorescence, and structured-light 3D scanning — in cultural heritage conservation anywhere.

The oasis view facing the Kizil Cave-Temple Complex in Baicheng county, Xinjiang Uygur autonomous region. [Photo by Fang Aiqing/chinadaily.com.cn]

For Cave 38, large language models have been employed to assist digital restoration and to logically fill missing or damaged sections of the murals, especially figures and decorative patterns, based on historical materials, the cave's overall artistic style, and remaining traces of the original work.

More broadly, Zhao said two phases of digital conservation have been completed at Kizil, including high‑precision scanning and high‑definition image capture of 22 caves. The academy has worked with universities and cultural heritage organizations across China on the effort.

The work takes on added significance given what Kizil represents historically. Miao Lihui, director of the academy's cave-temple archaeology and art institute, said the site is where Chinese civilization converged with cultural influences of India, Greece, Rome, and Persia. It was also a pivotal site for the local adaptation of Buddhism.

The statue of Kumarajiva (344-413), a master Buddhist translator, stands at the entrance of the Kizil Cave-Temple Complex in Baicheng county, Xinjiang Uygur autonomous region. [Photo by Fang Aiqing/chinadaily.com.cn]

The ancient kingdom of Qiuci, also known as Kucha, whose remains are distributed across Aksu prefecture and Luntai county in the Bayingolin Mongolian autonomous prefecture, had a thriving economy and an open, cosmopolitan culture that drew monks and pilgrims from across the ancient world. It also served as a military, political, and cultural hub for central Chinese dynasties in administering Xinjiang. Among its most influential figures was the monk Kumarajiva (344-413), who traveled to Chang'an and translated numerous Buddhist scriptures into Chinese. The site was inscribed as a UNESCO World Heritage site in 2014 as part of the Silk Roads: the Routes Network of Chang'an-Tianshan Corridor item.

According to Zhao, a digital exhibition center is under construction about 7 km from the Kizil Cave-Temple Complex, where replicas and virtually restored caves will be presented side by side for comparison. Kizil's history and Qiuci's iconic mural art, song and dance, and architecture will be presented through immersive visual experiences. The main building is expected to be completed soon, with parts of the center set to open by the end of this year.