Through a video link-up, Chinese President Xi Jinping and Russian President Vladimir Putin inaugurated the China-Russia east route natural gas pipeline on Monday.

The pipeline, which Putin called "the world's biggest construction project", extends more than 5,000 kilometers inside China and about 3,000 km in Russia. Overcoming extreme environmental and geological conditions, it adds a new tangible economic bond to the already close bilateral ties.

Xi said the project serves as a model of cooperation and that "the development of Sino-Russian ties is and will be a foreign policy priority for both our nations".

The project's significance is hard to overestimate.

For Russia, it opens up a new, reliable income stream, which is more than precious for Moscow amid Western sanctions, as the project will create jobs and infrastructure in Russia's Far East.

According to a 30-year, $400 billion deal inked in 2014, Russia will provide China with 38 billion cubic meters of natural gas each year when the project is fully operational by 2024. That would be 14 percent of all the natural gas China consumed in 2018, or about 28 percent of overall Chinese annual natural gas imports.

The pipeline will certainly provide a substantial boost to the struggling Russian economy. Besides being a steady cash stream, the pipeline is expected to be a rare, strong job creator and development accelerator for areas along it, especially the remote, underdeveloped Siberian regions.

For China, the pipeline is its first strategic cross-border gas artery. Passing through Heilongjiang, Jilin, Liaoning, Hebei, Shandong, Jiangsu provinces, the Inner Mongolia autonomous region, and the ultra-large cities of Tianjin and Shanghai, it will benefit the entire northeastern region, as well as Beijing and the country's most advanced coastal belt, considerably diversifying and stabilizing the gas supply for the areas involved.

While economic calculations were an essential part of the cross-border project, its strategic significance means there were more than just economic sums involved in the reckoning of its worth.

China's pursuit of good-neighborly ties determines it will not forsake any opportunity to develop friendly ties with any neighboring country. But external pressures have played a role in driving Beijing and Moscow closer. Like any countries, they need meaningful support in such circumstances, and they have found it in each other.

The project would not have been possible had China-Russia relations not reached their current level. As the leaders of both countries have observed on various occasions, the relationship is at its historical best, making it possible for both sides to cultivate their relations with a long-term perspective.