Thanks for the replies. I've done some more research, and I think that Japan's transmission standard is ISDB-T.
As I understand it, Japanese digital tv has everything flagged to "Copy once", and "move" also seems to count as a copy. The Vaio TP1 allows you to burn recorded programs to DVD (obviously downconverting everything to SD) and then automatically deletes that program from your hard disk. I will also subscribe to a digital satellite package, which I expect will be even stricter in it's limitations.
Also, the Vaio seems to use it's own software "VAIO Digital TV" to record the programs. But they are manageable/playable in the bundled Microsoft Media Center (Vista Home Premium) I think.
I forked out for a nice big Sony bravia tv, and bought the Sony DT-1 digital tuner yesterday.
(
http://www.ecat.sony.co.jp/vaio/acc/acc.cfm?PD=26654)
But my aging sony vaio laptop wont be able to record or playback anything I record, so I also ordered a customized Sony Vaio TP1.
http://www.vaio.sony.co.jp/Products/TP1/(Didnt make it down to Ginza Magic Randy. Went to Bic camera in shinjuku in the end. They have an "owner made" counter where you can customize your order).
I will obviously try to import and playback some recorded tv into jriver MC and report on how it all goes, if anyone is interested, when the computer arrives (sometime next week).