I remember the expression on a Norwegian colleague's face when I tried to get him to refer to Tokyo's underground railway network as "the subway" and not "the metro".

He thought I was being a dreadful pedant to insist that Tokyo's underground railway network is not known as the "metro" and "Tokyo Metro" is the corporate identity of one company that runs some subway lines.

Well... I am a dreadful pedant... but I was only trying to help.

I do think it was a mistake for "Eidan" to change its name to "Tokyo Metro".