(1) The small chessboard is subjected to gravity G, attractive force F on the chessboard surface, elastic force N and static friction F, so (1) is correct.

② The attraction of chessboard to chessboard is balanced with the elasticity of chessboard to chessboard, and the static friction is balanced with the gravity of chessboard, so ② is correct.

③ According to the balance of two forces in the vertical direction: f=G, and f should not exceed the maximum static friction, then f < FM = μ n = μ f.

F must be a constant, so that the maximum static friction force should be increased. For this reason, μ should be increased, and the surface of the chessboard should be made of rough materials, so ③ is correct.

④ When g > FM = μ n = μ f, the chess pieces will slide down, which may be too heavy or have no magnetism, so ④ is wrong.

Therefore, choose: B.