Probably some fringe Japanese Catholics took part in Jubilee 2000 Okinawa events. But I'm afraid all the others did not know about it. On the one hand, Japan is one of the biggest creditor countries but, on the other, the idea of 'jubilee' rooted in the Hebrew Bible carries little meaning here.
Christians are less than one per cent of the population of Japan.
Among the 480 plus 300 parliamentarians you can find only a few Christians. The Catholic Bishops' Conference in Japan is virtually nobody in the wider social context, and the bishops and their committees did not release a statement on the G8 meeting, although they had made lip service on debt cancellation. So, they were naturally concerned with the heavy US military presence there, and international issues including poor countries' debt were less important. But there is another perception gap between Europe and Japan. For you, Africa is just down there.