Given what was signed and agreed upon yesterday alone, Japanese Prime Minister Yoshihiko Noda's two-day visit to China has been at once substantive and efficient.

The People's Bank of China confirmed that the Japanese government's application to invest in Chinese government bonds is currently being processed. That signals confidence that will resonate beyond the financial field.

There's no doubt that it is a substantial step forward for the internationalization of the yuan, because for the first time the Chinese currency will become part of the foreign exchange reserve of a developed economy. The endorsement by the world's second-largest foreign exchange reserve holder is an essential boost to that process. The new channel for bilateral collaboration is expected to benefit both sides in coping with international financial uncertainties.

Economic exchanges have remained the most vibrant mainstream of bilateral interactions, despite all the vicissitudes in the capricious political ties. That is why a phrase has been coined specifically for this particular relationship: zhengleng jingre, or literally "cold in politics, warm in economy". But these ties cannot always stay on separate tracks.

Noda's harvest from his visit will provide additional evidence that when the political climate warms up, economic interaction will get even warmer.

That economic exchanges have survived the frequent ebbs in political relations reveals a shared understanding between the two countries - they are mutually beneficial and indispensable for both. That is precisely what generations of the two countries' leaderships have expected from our overall relationship. Or there would not have been the common initiative to build it into a "strategic partnership of mutual benefit".

Such a partnership, however, entails common endeavors to properly address, and in some cases rise above, the many sensitive issues threatening to poison bilateral relations.

The absence of mutual confidence, an essential cornerstone of any successful partnership, has made flashpoints in Sino-Japanese ties such as overlapping territorial claims in the sea even more difficult to handle.

The stark economic reality - that Japan is our second largest trading partner and we are its top trading partner and export market - indicates neither of us can afford to make an enemy of the other.

Noda's visit, the first by a Japanese prime minister since 2009, is a timely boost to the two countries' thawing ties, just in time to set a friendly tune for next year's 40th anniversary of the normalization of bilateral ties.

The upcoming commemoration will raise bilateral ties to a new level. But to achieve that, there also has to be the support of friendly feelings at the people-to-people level.