Thanks for the plug, Peregrine Falcon!

That is correct; it is not possible to make a Known Worl 901 game.

Unfortunately, after it was first ported over to the site, it was discovered that there was a critical bug in order processing (iirc, with the netural units) that made the variant unstable. Since some games were completed, the variant data must remain on the site, although no future games are allowed. (We should probably note this in the variant info, as it is a common question.)

Nonetheless, it is a wonderful variant, so I highly recommend trying it out on our variant-focussed sister-site, vdiplomacy: https://www.vdiplomacy.net/variants.php?variantID=57

Known World 901 is listed on the Variants page but not available when making a new game?

edit: please note that I tried to search for this in the forums, but I keep getting a 'high load' error