Being on Tue uploaded a video notice for the upcoming Being Guitar Summit 2020 Vol.08 that will take place this coming Sun & next Mon at Blue Note Tokyo
Interestingly , the video includes old footages from Being Guitar Summit Vol.03 which was held 5 years ago :
https://www.youtube.com/watch?v=-ei-P-DlDh0
Unfortunately I don't know what song the 4 guitarists played in the video but I do know that footages from Being Guitar Summit Vol.03 were included in the 1st DVD of 2016's Being Guitar Summit ~Greatest Live Collection~ release