Japan and Turkmenistan have signed business deals worth more than $18 billion.
The energy and infrastructure agreements were signed on October 23 during a visit to Turkmenistan by Japanese Prime Minister Shinzo Abe.
"We planned to sign documents on a number of projects in the chemicals sector and power station construction for a total sum of more than $18 billion. These documents have just been signed," Abe said.
Earlier, Abe held talks in Ashgabat with Turkmenistan President Gurbanguly Berdymuhkammedov?
The leaders welcomed participation by Japanese companies in building gas processing and chemical plants, according to a statement issued after their meeting.
Turkmenistan has the world's fourth-largest natural gas reserves.
According to the Japan Times, Abe is the first Japanese prime minister to visit Turkmenistan.
Abe is on the second leg of a six-nation weeklong tour that will also take him to four other Central Asian states.
Observers say the trip is intended to counter China's growing influence in the resource-rich region.