Starting on July 26, 2021, players can unlock a new song through the BEMANI PRO LEAGUE Stamp Rally event.
「Uh-Oh / kors k」
To unlock the song, go here and login with your KONAMI ID, go to the stamp page and watch all of the match videos (you only need to click the link, you do not have to watch the videos in their entirety.) You collect a stamp for each video watch. Get all the stamps and then play the game to unlock the song!