there is no fundamental reason for currency to lose 5% in 4 weeks other than technical reasons..i know the reason but won't say it don't want to accuse anyone of market manipulation. japan central spent 1-3 billion and to weaken the yen and it didn't do a damn thing...even the central bank of japan can't manipulate the forex so who what is moving the USD/g7 currencies? yuan isn't traded and is pegged,,,yuan is undervalued since every currency has appreciate against the USD by at least 30% USD is now cheap or undervalued versus the yen,pound, swiss, cad, china has no choice but to repeg the yuan.
i am technical trader . i am develop system of change of trend. this kind of movement its of few days *weekly TF, not monthly TF technicals reasons 1-sell off of usd yesterday 2-usd trend down but not the worst in the week. 3-usd show some strengh in some minors TF.H4 TF. 4-usd not is the worst in weekly TF. why? because on 09/15 usd broke key res to long against jpy (remember BOJ intervention) my system based in thats 4 reasons. good luck
Until Japanese parliament change its banking law, and raise its debts cap, BOJ intervention is extremely limited. I don't believe yuan is undervalued as many claimed. In both cases, American influence is very important, yen and yuan will move same direction which is in the best interest of American.