The study of correlation is the key to the success of many traders. Let us take the events of the week. The Japanese government intervened in an attempt to control the strength of the yen earlier in the week and the immediate results are all to plain to see.
Now the Euro is living on a knife edge due to the ongoing melodrama that is now labeled the Greek crisis but is actually the struggle for confidence in the Euro project.
You can see from the EUR graph that the intervention was ineffective. Within hours the yen again had the same buying power against the Euro. There is however some support for the USD v the Yen. As traders we can see that the USD has more support than the Euro this week and should looking out for further short selling opportunities on the EUR/USD.