If Yuka wants a reasonably clear name and the community actually has any interest in resolving whether he cheats or not a challenge wouldn't be that difficult to organize. This isn't a court of law so it's not really a case of innocent until proven guilty, if nothing further happens he'd always be muttered about much as walter has been. Yuka supposedly took a large step up in ability, which if he were cheating should make it easier to spot than it might be for some others so I propose that at an arranged time, in something like 2 sessions he play a series of games against players like spartie. He may perform a little worse than normal due to pressure, that would be understandable, but it would, if he were legit fairly easily demonstrate that he can play at that level.