New Zealand has, with good cause, always harboured mixed feelings about Japan joining the Trans Pacific Partnership. On the one hand, the inclusion of such an economic heavyweight would obviously add considerable substance to a finalised free-trade agreement. But Japan's history of protectionism, allied to the prospect that it would slow the progress of negotiations, suggested a need for caution.
There was no way its late arrival could be allowed to undermine the "gold-standard" pact that has always been Trade Minister Tim Groser's ambition. Now, that aim will be put to the test, with the 11 countries already in negotiation agreeing to allow Japan to enter.
Happily, there is some reason to view Japan's inclusion in the talks from July with optimism. Mr Groser has provided an assurance about its commitment to achieving an ambitious and comprehensive agreement, including agriculture.
It also wanted this to be set in place as soon as possible, he said. If there are doubts, it is because such pledges fly in the face of Japan's tradition of closing its border to imports, especially agricultural products. For the United States, the first of the heavyweight economies to join the TPP negotiations, there is also the matter of high tariffs on imported cars.
The Japanese, however, seem to have woken up to the fact that there is not much future in closing themselves to foreign competition any more. And that in a world where trade is viewed as a universal and unequivocal benefit, a price would have to be paid for maintaining its protectionist tradition.