Regular trading hours for this stock on its primary exchange (in Tokyo) are from 09:00 JST - 11:30 JST, then it closes for 1 hour, then it reopens and trades from 12:30 JST - 15:00 JST. On top of that, trading runs continuously from 08:00 JST - 16:00 JST on non-primary exchanges.
1.53M is the volume according to the primary exchange (link below). The hourly data being displayed by Yahoo is a combination of primary and non-primary exchanges. The 11 a.m. hour is blank because the stock closes temporarily from 11:30 to 12:30 -- this is obviously wrong yet this is how Yahoo reports it nevertheless.
It is probably a better idea for you to look for another data source. Looking through this post might be a good place to start: What data sources are available online?
You can find data from the primary exchange here: Japan Exchange Group