The Bank of Japan monetary policy statement is due Thursday 17 September 2020
The BOJ does not have a scheduled time for their policy announcement. In the 0230GMT to 0330GMT time window is usually a good bet though.
There is no change in policy expected from the Bank today so earlier in that window is more likely than later. The only caveat is that with a new boss (Japanese Prime Minister Suga took the reigns only yesterday) the Bank may have a bit more to say than normal.