This indicator draws a vertical line at 8:45 a.m (GMT+9), the start of the day session.
It is also possible to change the time at which the vertical line is drawn.
In true TradingView spirit, the author of this script has published it open-source, so traders can understand and verify it. Cheers to the author! You may use it for free, but reuse of this code in a publication is governed by House Rules. You can favorite it to use it on a chart.