The factors mentioned above can also cause a currency to decline. For example, the currency of a country with low inflation will generally rise because that country's purchasing power is higher relative to other currencies. Even natural disasters such as earthquakes or tsunamis, which put a strain on a nation’s economy, can have a negative impact on a currency.
There is an additional rule for trading when the market state is more favourable to the system. This rule is designed to filter out breakouts that go against the long-term trend. In short, you look at the 25-day moving average (MA) and the 300-day moving average. The direction of the shorter moving average determines the direction that is permitted. This rule states that you can only go:
If traders are positive on the prospects for the Yen, they would expect the number on the right to go down – i.e. the Yen would be getting stronger against the Dollar. Traders would be buying less Yen with a Dollar as the Yen got stronger. Similarly, if the Yen was expected to weaken, forex traders would expect the Yen number to go up, reflecting the fact that the dollar could buy more yen.