Questions to ask each morning:
- How far did USDJPY move after the release, compared with a normal Asian session?
- Did the move hold, or was it reversed before London?
- Is there related news, for example comments from Bank of Japan officials?
For London scalpers: mark the Asian high and low after Japanese data, since those become levels for the morning.
The bigger events are BoJ policy decisions, which often come during the Asian morning, and Tokyo CPI. Those can affect yen pairs into the London session.
Writing down the Asian reaction each morning in one line builds a record that answers the question for your own pairs over time.
How do you handle Asian news on yen pairs?