South Korea, which sends around a quarter of its exports to China, is one of the few countries in the world to run a trade surplus with the Asian giant.
Both countries want more of this trade to be done in yuan, which would make trade cheaper by avoiding the need to convert funds into US dollars or euros before completing trades.
Earlier this year, South Korea became one of the newest offshore yuan trading centers.
"What the (South) Korean government has done is make sure that the country enjoys the full benefit of keeping the money onshore," said Wenlin Juang, head of market development for North Asia with news agency Thomson Reuters.
South Korea is not alone in pushing to do more business based on the Chinese currency, particularly in Asia where the Chinese mainland is the largest trading partner of many countries in the region. In fact, rare is the country in the region that is not working hard to take a larger chunk of yuan-denominated business.
The yuan's momentum will get a fillip if the International Monetary Fund includes the currency in its Special Drawing Rights basket in October.
This would make the yuan one of just five global currencies included in this elite pool of global reserve currencies. At the moment, the SDR includes the US dollar, the euro, the British pound and the Japanese yen.
There are more than 60 central banks around the world that invest in the yuan, and China has currency swap agreements with 30 countries. As of April, currency swap deals had added up to 3.14 billion yuan ($500 million).
In Asia and surrounding regions, the Chinese mainland has agreements with South Korea, Malaysia, Indonesia, Singapore, New Zealand, Uzbekistan, Mongolia, Kazakhstan, Russia, Thailand, Pakistan, Australia, Sri Lanka, Qatar and Nepal as well as the Hong Kong and Macao special administrative regions.
"The use of the RMB outside the mainland has picked up a lot of speed in the past few years," Vincent Lee, executive director of the Hong Kong Monetary Authority, said at a conference last month.
"We can now use the RMB for all trade-related transactions with the mainland and increasingly we can also use the RMB either for people investing into the mainland, or for mainland people, if they want to take money out of the mainland and invest overseas, they can also use the RMB."
The HKMA is working to leverage its position as the regulator in the largest offshore market in the world and is taking its show on the road to Malaysia and Thailand, among other countries, hoping to expand the use of the RMB and ensure more of that money flows through Hong Kong.
The new reality-that there is very little that cannot be done in global trade or finance using the yuan-may prove to be good news for China's Asian trading partners.
Many have long relied on the US dollar for international business and investment, even as their relationship with China has grown in importance in terms of magnitude.
With the dollar strengthening, many of these countries are questioning the wisdom and economic impact of a total reliance on the greenback.
Malaysia, Indonesia, Singapore and South Korea have emerged as key players in global yuan markets, complementing the strengths of Hong Kong, Macao and Taiwan, and acting as a springboard for a more overseas reception for the yuan.
And as the dollar has appreciated against other international currencies, the yuan has remained steady and is now closer to being fairly valued than it has ever been.
In fact, the International Monetary Fund is getting ready to make an official statement to this end sometime this year. Officials have been hinting at this possibility for several weeks.
"Since last year we have seen, as you have noted, a very significant appreciation of the RMB in real effective terms," said Markus Rodlauer, deputy director and mission chief for China at the IMF, during a media briefing in mid-April.
"It has been mostly stable, depreciating a little bit against the dollar because, as the dollar went up, in effective terms, (the yuan) has gone up by more than 10 percent.
"If you add that up, last year (the yuan was) moderately undervalued and now it has gone up," said Rodlauer. "We are now reaching a point where we are close to it no longer being undervalued."
The IMF is now updating its 2014 assessment and an official report will come out later this year.
For the time being, the overall dominance of the dollar in world trade is assured. The greenback is by far the most used reserve currency in the world, but the yuan has emerged as a well-priced alternative.
A number of disparate factors suggest that the influence of the yuan is only likely to grow.
The first is the increasing likelihood that the IMF will include the currency in its SDR.
In October, the IMF will carry out a five-yearly review of the currencies included in the SDR basket. And "one important issue in the review will be whether the RMB will be included", Zhou Xiaochuan, governor of the People's Bank of China, said last month at the IMF's International Monetary and Financial Committee.
China started moving toward "gradually making the RMB a convertible currency" in 1993, Zhou said.
The yuan is now "largely convertible" for foreign direct investment and outward investment and there are investment programs for both foreign and domestic investments.
"At present, there are only a few capital account items that are completely inconvertible," he said.
