Ruling use of irregular blade

A player used a penhold blade, one side wooded surface black painted and on the other side regular black rubber, the player won the game and the fact of equal color on both sides was only brought up half an hour after the game was finished.

What should happen now, valid the game because no claims were made before and during the game or should the player be disqualified and the game given to his opponent?

Hi Rene,

I think that the match result still stands.

He would not be able to use it in future matches though.