When western credit markets seized up five years ago, it provided an opportunity for Japan. Although tough to crack, with deals often taking three months, Samurai bonds (issued by non-Japanese companies in yen), became more attractive. And having been through the pain of gaining access, those that went in are staying the distance, and the number of newcomers is growing.

Ashley Curtis, a debt capital markets banker at Nomura, said: "European and US markets have repeatedly opened and closed in recent years in response to the financial turmoil but, throughout that time, the Samurai market has stayed open."