On the 28th February, Sega announced 'Sega Fes', a Sega Festival held in Akihabara on April 14-15, 2018.
The 'Sega Fes' is meant to be a celebration of Sega, both old and new, and of particular interest is a 'surprise announcement' taking place during the event, that's 'unique to Sega' (apologies for the google translation):
I take from this that there's a surprise announcement, tournaments and a live stream of the event.
Could this be something Virtua Fighter related? Consider first everything we went over in the JAEPO Speculation thread.
Also worth noting they mention:
Tournaments - Perfectly suited to something like Virtua Fighter.
The event is Held in Akihabara - The spiritual home of Virtua Fighter, with the most populated Virtua Fighter Arcade being Club Sega Akihabara, where possibly the best players in the world convene on a regular basis.
Sega Fes 2016 saw AM2's previous game announced - AM2's Souls Reverse was announced at the last Sega Fes, held in 2016. Could they be making back to back reveals?
Considering this event is meant to be a celebration of 'Sega old and new' Virtua Fighter would certainly fit the description as one of Sega's enduring legacy franchises.
It's worth noting that some games people suspected might be the 'Surprise Announcement'; Sonic Racing and a new Shining Force Spin-off have already been announced. In theory this excludes them from being the 'Surprise Announcement' at Sega Fes.