China and Kazakhstan see this as a mutually beneficial relationship
Chinese President Hu Jintao has unveiled the Kazakh section of a 7,000km (4,300 miles) natural gas pipeline joining Central Asia to China.
Mr Hu was joined by Kazakhstan President Nursultan Nazarbayev during the inauguration in Astana on Saturday.
The pipeline is part of China's attempts to secure more energy sources worldwide.
On Monday, Mr Hu is due to head to a commissioning ceremony in Turkmenistan where the pipeline actually begins.
He is also expected to be joined there by President Islam Karimov, the leader of Uzbekistan - the fourth country involved in the project.
Mr Hu and Mr Nazarbayev together pressed a symbolic button to open the 1,833km (1,139 mile) section before officials from both countries marked the new relationship with hugs and cheers, the Reuters news agency reported.
Mr Nazarbayev said: "This is a grand construction project that will in time resurrect the ancient Silk Route."
The pipeline, which begins near a Turkmenistan gas field being developed by the China National Petroleum Corporation concludes in Xinjiang in western China.
It has an estimated capacity of 40bn cubic metres a year and will mean the central Asian countries are less dependent on Russia buying up their supplies.
This is Kazakhstan's first export route that does not go through Russia. This segment cost $6.7bn (£4.12bn) and was completed within two years.
Most of the finance for the project came from the state-run China Development Bank.
The whole pipeline is expected to be finished by 2013.