BEIJING/NEW DELHI (Reuters) - As U.S. President Donald Trump and some of America s democratic allies talk up a vision of  Indo-Pacific  cooperation, China is determined to ensure that the future belongs to  Asia .   The increasing use of the phrase  Indo-Pacific  by Trump and his team during their marathon Asian jaunt this week, instead of the  Asia-Pacific  term that has long been common in business and diplomacy, is being greeted with thinly-veiled sneers in Beijing.  Trump choosing to use the term and actually making it happen are two totally different things,  Diao Daming, an American studies expert at Renmin University in Beijing, told a forum on Friday.    The region is leading global development and Trump wants America to be first, so he could not ignore its existence. He had to say something to the region, so we have  Indo-Pacific . But as yet it s just a concept and we don t know what it means.  Beyond the wordplay lies both concern and scepticism in Beijing at U.S. attempts to complicate China s strategic domain, particularly by encouraging rival power India to work more closely militarily with Japan. Tokyo recently backed New Delhi during India s border stand-off with China.    Chinese Foreign Ministry spokeswoman Hua Chunying did not dignify  Indo-Pacific  by name in a statement this week, but noted that  this concept has been mentioned many times .    We hope that the Asia-Pacific region can become a stable, prosperous and orderly region....where we are capable of managing differences and have the wisdom to resolve the disputes,  she said.    Indo-Pacific  has grown in usage across diplomatic and security circles in Australia, India and Japan in recent years, shorthand for a broader and democratic-led region in place of the  Asia-Pacific , which to some places an authoritarian China too firmly at the center.   Trump and his team have given it fresh currency in recent days, starting in Seoul and Tokyo, building on the rhetoric of his secretary of state Rex Tillerson, who last month talked of the need to support a  free, open and thriving Indo-Pacific .   Describing the Indian and Pacific Oceans as a  single strategic arena , Tillerson went further as he described India and the United States as  bookends  within that region.    In concrete terms, it will lead to great co-ordination between the Indian, Japanese and American militaries including maritime domain awareness, anti-submarine warfare, amphibious warfare, and humanitarian assistance, disaster relief, and search and rescue,  he said.   Not all allies are convinced, however.   When Trump s White House issued a statement after the U.S.-South Korea summit on Wednesday describing the alliance as a  linchpin for stability, security and prosperity in the Indo-Pacific , South Korea s presidential Blue House issued a note of caution.   While the phrase  Indo-Pacific  matched some of South Korea s policies aimed at diversification,  we felt there was more discussion necessary to see whether it is an appropriate term to be used in our efforts toward...joint strategic goals , the Blue House statement said.   Welcoming the trend is Indian navy Captain Gurpreet Khurana, who was among the first to coin the Indo-Pacific concept in an academic paper back in 2007.   The rise of India as an economic power following its free market reforms and then its gradual military build-up was itself a key factor in the increasing significance of the Indian Ocean, he said.    India could no longer be excluded from any over-arching reckoning in the Asia-Pacific, be it economic or security related,  said Khurana, of the military-funded National Maritime Foundation. Chinese officials and experts have long bristled at any perceived attempt to contain a rising China.  But Trump s Indo-Pacific policy should not be underestimated by China, because India, Japan and Australia are united by being on the wrong side of China s development strategy for the region, according to Jia Wenshan, an expert on China s foreign policy at the Beijing-based Center for China and Globalization.  China needs to as soon as possible deal with the Indo-Pacific alliance, as it is absolutely in conflict with Belt and Road,  Jia said, referring to the Chinese president s signature initiative to re-establish trade and infrastructure ties between China and nations throughout Central and Southeast Asia.  Behind Indo-Pacific you have Japan s economic support, India s development speed and Australia s fears of China, these are all strategic realities.  