Heh, great story. Would have been even more interesting to see this medium play live.
Ofcourse this situation wasn't really fair on Kortschnoi, as Maroczy could use divine assistance! Its amazing he lost really... No wonder he died, couldn't beat Old Master Death at chess either.
On Bendcat's blog, under a posting on the web pages of chess masters, which included a link to a page on Jacque Mieses, the following was posted:
billwall: Very good, but Mieses has been dead for a few years. Hasn't stopped Korchnoi from playing him, though.
likesforests: Bill, this sounds like an interesting story. Care to explain?
For some reason I wasn't able to make a game board in a posting there, and rather than re-booting, etc. I decided to respond here (since Mr. Wall may not see the request).
In 1985 Korchnoi met Robert Rollans, a psychic medium from Switzerland. In the course of things, Rollins helped arrange a game between Viktor and the long dead Geza Maroczy (died in 1951). The game was actually a correspondence game conducted by mail over an 8 years period. Korchnoi won of course.
Details are available here