Originally Posted by CPH-Flyer

You can transit on separate tickets, just bring a print of your e-tickets to make it easier, and expect that check-in can take a bit longer than normal. You will probably get lots of emails aboutvth requiments to enter Japan, which will not apply to you. There are no document requirements for transit.

Haneda allows connections of up to 24 hours, and a 21:30 on day 1 and 01:30 on day two is operationally considered a same day departure.
​​​​​​