About this claim.
yamabiko (SINOBUZ Edition) is the first EXTRA STAGE song in beatmania IIDX that is a licensed song.
What about The Sound of Goodbye from 7th style? - Catastrophe
- The Sound Of Goodbye and REMEMBER ME are not EXTRA STAGE songs in the regular sense, they are just hidden songs that happen to be playable in the EXTRA STAGE. MAX 300 is a proper EXTRA STAGE, with its own song selection BGM and it is required to access 革命. --GlaringRadiokid (talk) 00:46, 4 March 2021 (UTC)