Quote from luisHK:
I meant I had buy orders @76.52 and 76.32 and the price went largely through.
Sorry my bad.
HAHAHAHA ...I actually thought you trade big or probably know someone quite big and know of two 'big' usdjpy buy orders go through -- something like 100s of millions in size.
Just a pun on myself - It seems I assume everyone on ET is trading millions in positions

LOL
OKAY, here is my analysis of what happened. Below are few of the major reasons why big moves might happen in usdjpy particularly. Not sure which one (if any) applies to this situation:
1. Retail positioning is long 10:1 dollar yen, almost all of these trade using a high margin 10:1 to upto 30: 1 or even more. Its easy for a group of bank dealers in NYC banks to go for drinks on Thursday evening and decide that they are going to sell usdjpy nyc morning and stop all these retail crowd out of their trades. Assuming it takes 200-500 million in USDJPY sell in 30 minutes to push the price down, if you assume 10,000 retail guys being leveraged long 100k usdjpy in all, that gives around 1 billion long usdjpy retail position. Assuming 50% of them will have stops upto 75.95 (previous low), its almost guaranteed for bank guys to sell massively and then cover effortlessly, leaving them a big friday profit. Now, ofcourse you gotta have MDs/head of tradings desk involved in this sort of maneauvor as an associate or a VP wont be able to sell 200 million of usdjpy w.o any approval from above.
Most likely, this scenario is not applicable today since price hasn't reversed back yet.
2. Another hypothesis, you had some huge really huge 76 strike digital option expiring and the bank or the counterparty decided that it wants to move the price. This is not the case today since cut-off time is 10AM NYC for fx options, and the drop happened much before 10EST.
3. This is QE3 speculation driven
4. Europe efforts this weekend and over the next few weeks to fall short of required - this hypothesis lead some macro hf to sell large amounts of usdjpy, thinking this risk-off catalyst might be the thing that breaks off usdjpy recent range finally.
I think its either 3rd or 4th scenario in play today - but who knows really what caused this drop...All this is guessing i am doing.