Paul Corfield wrote:

however I did not venture on to the private lines or into the suburbs
where I expect the language on signs issue would tilt very heavily
towards Japanese only.

It is harder but the way I did it was to just get on the first train
noting the symbol for the station, then check the next station on my map
and if wrong get off and go back the other way. Theres a 50-50 chance of
being right.

Having clear directions at the destination is vital too..

mf