For newer traders.
The Monday morning pre-Tokyo market is open, but liquidity is very poor. There’s an interbank market in New Zealand, then Australia. There’s EBS and Reuters Dealing (think of them as sort of ECNs for banks).
Prices can gap on very few deals, or on none at all. Then move towards filling gap (or maybe not), again on maybe very few deals.
Here are some 10-minute bar charts from Reuters. Even these don’t necessarily tell the complete story.