https://allusion-tokyo.com/tatsujin-m/
Raiden II/DX/III/IV composer Sato-san is doing this event next year in Tokyo. Apparently he and some other cool people feel like celebrating Tatsujin for some reason, so they're doing this. His band will be playing music from Tatsujin live with legendary Toaplan programmer/composer/game designer Uemura-san's band and also Asuka 120%/YU-NO composer Yonao Keishi's band, and then some members from all three bands are going to play some stuff together as well. After that there's the fan meeting, so if you want to talk to anyone and/or if you have PCBs or other games or soundtracks or whatever else that you want signed, this is your chance. Whenever Uemura-san plays live, there's always a bunch of other cool people from Toaplan, so there is a very high chance that you might run into someone cool beyond just the people that are going to be performing.
Important: if you've never been to a livehouse before, it's very, very loud. I highly recommend bringing some earpro if that's something that you are concerned with. If you don't, you can expect your ears to ring for a while.
Price is 4100 yen for the live (3500 for entry + 600 for 1 drink) and an additional 3000 yen for the fan meeting, to be paid at the door.
These things are a lot of fun, so if you are planning on being in Tokyo on that day, check it out. I am currently planning on being there. I don't think any of these guys can do any language other than Japanese, so if you need a Japanese <-> English interpreter or don't know who any of these guys are, come find me.