I don't agree fully. With the rail network I think it's pretty much the same in Japan as in the UK - since you have one set of rails going from point A to point B for most (A,B), it's not a liberalisation in either countries. With postal services we have to look at packages and letters separately - the former market is completely liberalised, for the later JP still has a de facto monopoly - that doesn't mean you're not allowed to create your own letter mailing service though, it's probably just that you can hardly match them at their price point.

So I don't think Japan's case is that much different from the UK from a market perspective and I'm not quite sure whether the ideology is that different either - if you (as in the premier minister responsible for it) don't have a free market ideology, why putting privatisation on your flag at all?