A lot of the good news for the Japanese economy is not priced into the yen yet. If the flow of money abroad from Japanese investors slows that will allow the growth story to come to the fore.

The equity market's strength is going to continue and that's proving a great attraction for foreign investors. That will help the currency somewhat and is indicative of an economy that is outperforming its peers.

The fact that Fukui is backing away from the optimism rates will go up could prove a bit of a problem for the yen. Investors are looking for some follow through from policy makers in order to be confident about pushing the yen higher.

For the last couple of months there has been a buildup of economic optimism in Japan. Any evidence the pace of expansion may slow can have a negative impact on the yen.

In terms of any macroeconomic shock, it is all going to come through the oil price.