Because that move was driven by the USD - you can see the opposite move in GBP/USD.
Here is the same chart also on 15min TF (GBP/USD)
Notice how your pair above is USD/JPY = USD/XXX
My pair below is GBP/USD = XXX/USD
So they are inversely correlated.
I’d say the move was driven by the US, specifically this?
It’s all very well speculating on patterns, but you have to keep up with the news releases too, especially high risk “hearsay” rubbish - such as a speech.