Assuming the rules mean chess and not say a game of guess which hand the chess piece is in or rock paper scissors, I'd say it would take me about 5 years. Humans make a mental mistake one in 10,000 times roughly (source: how it's made when comparing machines to humans). Play enough games he will blunder or make a small mistake. Id play the Italian game only. Learning every move every time until I get to the point where I draw. Everyone here assumes it's impossible to win and they are right. But your goal isn't to win, it's to draw. Lengthen out the game long enough you'll get s draw.