Japan, having lost out to South Korea in December on a $20 billion atomic contract with the United Arab Emirates, is testing the new approach with Vietnam before considering opportunities in Gulf nations such as Saudi Arabia, Tokyo Electric’s chairman said.

 “We learnt our lesson from our unsuccessful bid for the U.A.E. nuclear program,” Tsunehisa Katsumata said in an interview today in Abu Dhabi, which is hosting a two-day Japan forum. “We decided to set up a ‘one-stop shop’ because we understand that is what emerging-market countries need.”

Toshiba Corp. and Mitsubishi Heavy Industries Ltd. are among six Japanese companies in the venture as the country aims to compete with France, Russia, Canada, and the U.S. in the expanding global reactor market. Toshiba said July 12 it plans to pursue nuclear power contracts in Saudi Arabia. Vietnam said in June it plans to build as many as 13 atomic plants with a capacity of 16,000 megawatts over the next two decades.

The “all-Japan endeavor” would offer countries the “entire system,” from nuclear education to building and operating reactors, Katsumata said.

Saudi Arabia, the world’s biggest oil exporter, is one of several Arab Gulf countries seeking to develop nuclear energy to meet rising electricity demand. Kuwait and France signed a civil nuclear-energy accord in April and the U.A.E. will start operating four nuclear plants by 2020.

Asian nations such as Japan and South Korea, which import almost all of their energy needs, are eager to boost economic ties with the oil-rich Middle East as they seek supply security.

Since winning the U.A.E. contract, South Korean companies are increasing their foothold in the fourth-largest oil-producer of the Organization of Petroleum Exporting Countries. The two nations agreed on Aug. 2 to cooperate on energy exploration and stockpiling of crude oil.