When Japanese director Ryo Takeuchi appeared for his scheduled online interview with China Daily, he was sitting in a cafe near a historical site in Zhengzhou in Henan province.

"Look over here, the ancient wall behind me dates back 3,600 years," he said enthusiastically via his phone, pointing out of the window, before revealing that he planned to visit the Yellow River Museum the following day.

From May to June, Takeuchi traveled across the country to promote his documentary The Yangtze River, an acclaimed feature which has received a rating of 8.5 points out of 10 on the popular review aggregator Douban.

Moved by scenes that vividly reflect life along the titular river, viewers in cities along other rivers in the country also invited him to consider making their rivers the subjects of his next projects.

"In northern China, people expressed their desire for me to shoot a documentary about the Yellow River. When I visited cinemas in southern cities like Guangzhou and Shenzhen, people recommended that I make a documentary about the Pearl River," says Takeuchi.

In Zhengzhou to attend a cultural activity, Takeuchi explained why he had seized the opportunity to explore the history and culture of the city, a historically significant location along the Yellow River.

The director, who is from Chiba prefecture near Tokyo, first came to China to produce a three-episode documentary A Journey to the Yangtze River for Japanese public broadcaster NHK in 2010. Despite being unable to speak Chinese, he developed a passion and curiosity to explore Chinese society and since 2013, he has been living in Nanjing in Jiangsu province.

Now a fluent Mandarin speaker, he and his wife, Zhao Ping, a Nanjing native, have co-founded a company, and have produced a series of documentaries that show China and Chinese people from a foreigner's perspective, among them films like The Reason I Live Here (2015) and Long Time No See, Wuhan (2020).

The Yangtze River, which the witty director humorously refers to as a tribute to his mother-in-law, given its status in China as the country's "mother river", enabled Takeuchi to fulfill his decadelong dream of retracing the route along the river, which runs for just over 6,300 kilometers in length.

The driving force behind the new documentary was his desire to visit the place where, in his own words, he could see "the first drop of the Yangtze River" emerge — the glacial meltwaters of the Tangula Mountains on the Qinghai-Tibet Plateau.

Regrettably, due to altitude-induced stress, he was unable to walk the last few hundred meters to reach the source, and instead entrusted the task of filming it to a younger fellow cameraman.

"But I don't see that as a setback. If I reached there effortlessly, the documentary wouldn't have been able to effectively demonstrate how challenging our journey was," says the 45-year-old with a smile.

The documentary also reveals the great changes to the regions along the Yangtze River, reflecting China's transformation as a result of substantial economic development in the decade since he shot his first documentary series.

In 2010, Takeuchi sailed the river aboard a modest cargo vessel. When he reunited with the ship's owner, Jiang Hong, for the new film, he was impressed to discover that the ship had since been equipped with a Beidou Navigation Satellite System.

Additionally, as he and his crew were unable to wait for Jiang's ship due to their hectic schedule, Takeuchi took a cruise ship instead, and was delighted to discover that the accommodation was both luxurious and comfortable.

Venturing through the Three Gorges, he visited Yichang in Hubei province, where he was amazed by the city's ship lift — the largest of its kind in the world — a marvel of engineering that effortlessly hoists vessels weighing up to 3,000 metric tons up a vertical span of 113 meters, and which is a testament to human ingenuity amid nature's splendor.

"When I moved to China in 2013, life wasn't as easy as in Japan. But now, living in China feels more convenient. When I went back to Japan earlier this year, I realized I had to wait in line for a cup of coffee, whereas in China, you can order ahead on your phone," he says, adding that he hopes the documentary will help Japanese audiences get to know China better.

The sociable and observant director also turned his attention to the people living along the river.

At a dock in the famously mountainous city of Chongqing, he focuses on a group of workers using bamboo poles to carry luggage for passengers, who are known as "bang bang", the word for porters in the local dialect. His attention is seized by a 71-year-old, who has worked as a porter since 1994, and who earns 40 yuan ($5.5) per trip, even in scorching summer temperatures that can reach 40 C.

One of the most heartwarming scenes for many viewers is when the director re-connects with Rinchen Tsemo, a girl of Tibetan ethnic group in Yunnan province. When they first met, the young girl was 17, and was shy and introverted, but caught the attention of the Japanese crew as she tended to her job of posing with a lamb for tourists to take photos, for which she charged 5 yuan.

Moved by her curiosity about the wider world, Takeuchi and his crew took Rinchen Tsemo and her family to visit Shanghai. The trip proved to be life changing, and inspired the girl to work on securing a million yuan loan from a local bank to open a hotel a decade later.

In the new documentary, Rinchen Tsemo says that some of the design ideas were inspired by her trip to Shanghai, where she discovered for the first time that a hotel room could have a separate toilet and shower room.

"I feel like I'm the key that has unlocked a whole new world for her. Rinchen Tsemo has achieved her dream all because of her relentless effort and hard work over the last 10 years. I truly admire her dedication and drive," remarks Takeuchi.

The documentary, which has garnered acclaim in both China and Japan for its down-to-earth and engaging nature, has also received praise from industry insiders.

In late June, it won the best documentary award at the 21st China Movie Channel Media Focus Unit, an industry honor established in 2004 by the titular channel, the country's largest and most influential broadcaster specializing in movie broadcasts.

Wu Hailong, president of the China Public Diplomacy Association, says that the value of the film lies in the director's use of a documentary approach to objectively and truthfully tell the story of the Yangtze River to the world, reflecting China's development and the changes it is undergoing.

Contact the writer at xufan@chinadaily.com.cn