Spoke to my cuz yesterday and he is on a work trip to his companies head office in japan. He got told that they are going to be taken to the budokan for a look round! Luky sod. He's an obsessive bootleg collector so he's well aware of the importance and history of the place. Think he's plannig on asking questions about some of the acts of yesteryear but I suspect he won't have much joy. Its probably moved on since his idols ozzy and dio played there. No harm trying I suppose.
Will let you know if he comes back with any queen related info:-)