Hanoi has been considered a fraternal ally of Beijing. But Nguyen Phu Trong’s visit comes at a time when Japan and Vietnam are stepping up their cooperation in the wake of China’s muscle-flexing in the South China Sea, where Hanoi is engaged in territorial rows with Beijing.

Vietnam and Japan, Trong said, “need to raise the effectiveness of cooperation in education and training, science and technology, culture, tourism, labor and people-to-people exchange environmental protection disaster preparedness, climate change response, as well as in defence and security.”

Trong thanked Japan for being Vietnam’s biggest aid benefactor and sought its continued help, particularly in developing his country’s infrastructure as it strives to turn itself into a modern industrial nation.

“Vietnam looks forward to the continued high influx of ODA (official development assistance) from Japan, especially into infrastructure and human resources development, development of advanced industry and agriculture, response to climate change and environmental challenges, as well as economic management capacity building,” he said, while also seeking expanded Japanese investment in such areas as hi-tech and supporting industries.

Trong’s visit, in which he will meet with Japanese Prime Minister Shinzo Abe, will be his first to Japan since becoming general secretary of the ruling party in 2011.

Trong visited the United States in July, becoming the party’s first chief to do so since the end of the Vietnam War. He met with US President Barack Obama, and they shared concern about Chinese activities to press sovereignty claims in the South China Sea, viewed by both countries as not in compliance with international law.

Trong outranks both President Truong and Prime Minister Nguyen Tan Dung in Vietnam’s leadership hierarchy.

The party chief noted that when Vietnamese President Truong Tang Sang visited Japan and met with Abe in March last year, the two countries upgraded their ties to an “Extensive Strategic Partnership for Peace and Prosperity in Asia.”

He said bilateral cooperation has expanded, mutual trust has been consolidated and economic ties continue to grow strongly, especially in terms of ODA, foreign direct investment, trade and tourism.

“Building upon that momentum, Vietnam would like its partnership with Japan to further deepen with greater efficiency and effectiveness in all areas, especially in the economic domain,” he said.

The South China Morning Post - September 13, 2015