There's a great article, of March 16, 2016, on the Australian Naval Institute website. This is by Hugh White, Professor of Strategic Studies at the Strategic and Defence Studies Centre, ANU. This article at http://navalinstitute.com.au/risks-in-japanese-submarine-partnership/ first appeared in The Age newspaper.
"Risks in Japanese submarine partnership"
The article ends:
"What kind of co-operation will we get from Japan if in say, five or 10 years, with the project well under way but no subs yet delivered, Japan faces a confrontation with China and we don’t give it the support it expects? Why wouldn’t Japan walk away from the project, or start putting tight limits on what [sensitive submarine technology] it is willing to share with us?
That would be a disaster for the submarine project, and for our relations with Japan. So we’d be much better off keeping them separate. The beauty of the German and French bids is that their bids are so much simpler. They are only in it for the money, and that’s a good thing, because that is a price we know we are willing to pay."