So there is no direct correlation between mijin and NEM. They just use same API. or?
This is of course a question that is on everybody's minds.
Making direct connections between two chains, "side chains" or "Atomic Cross-Chain Transfers", is a very difficult process and nobody as of yet has come up seamless and easy to deploy working solution despite the idea being proposed years ago. One of the largest teams of most talented minds in crypto, which is basically an all-star team of who's who (Blockstream) has yet to demonstrate a good working product despite have a huge team and tens of millions of dollars in VC funding.
That said this is being researched into and considered by the devs, and in many ways a model where the NEM main chain is the intersection/birthing point of all the mijin chains is of course being investigated and is desirable. Also, NEM is not Bitcoin. The NEM devs have already made a long list of firsts that no other blockchain has done and things that probably can't ever be done on Bitcoin. First with PoI, first with Eigentrust, first with a new kind of spam protection, first time synced nodes, first with editable multisig with blockchain pushed notifications, first with delegated harvesting and so on.
But let me take a step back and talk about just the use of APIs by themselves. As of writing this in the the first 24 hours of the offer, we have had over 50 companies apply to test Mijin. This is in addition to a major bank and a business enterprise software platform that is integrating Mijin into over 5000 medium to large Japanese companies. These businesses can use Mijin to trade with other trusted partners in a secured way. It gets them into the blockchain game, but in a fully controlled environment that they can mandate and feel safe and secure about. After some time if these companies/bank don't want to just trade amongst their few trusted partners but everybody and anybody in an open-market, then in just minutes they can have their software updated to trade over the NEM main chain.
Finding a chain that has any real business being run on it other than Ripple or Bitcoin is pretty rare, and finding one that has a bank or large company is even rarer. It seems logical that if the NEM main chain can attract even a small percentage of trading from the companies that are using Mijin, it will be one of the top 5 blockchain platforms.