Back To Square One Meaning

Example :   After spending six hours on the intake we realized that there was nothing wrong with it, so we are back to square one.1952 Edward Maurice Hugh-Jones, The Economic Journal, “The American Economy, 1860–1940. by A. J. Youngson Brown”, p. 411:[2]  Withal he has the problem of maintaining the interest of the reader who is always being sent back to square one in a sort of intellectual game of snakes and ladders.