There’s been nothing new across the newswires to trigger the USD/JPY selling. We are running into cross buyers (i.e. Buying against the Yen) now.
Some are pointing to news of 3 Chinese ships entering waters near the disputed Senkaku Islands. Latest I have is this occurred on Saturday morning, and selling USD/JPY on this seems a little far-fetched. Nevertheless, USD/JPY has been hit hard.