no. Rook is easy, 2 bishops is easy, knight + bishop is tricky but not hard if you practice it, 2 knights is possible if he walks into it, and oddly enough, 2 knights and king against king and pawn is often forceable. Because the pawn allows you to move into a position that would otherwise be stalemate. Queen versus rook is tricky but very doable, what's REALLY tricky is some of those rook and bishop againt rook ones, but his king needs to already be on the edge to force it