Back to square one

Were does the phrase ‘back to square one’ originate? Where was the original square one?

 There are two main theories explaining the origin of the phrase ‘back to square one’:

1. Returning back to the beginning in children’s games such as hopscotch and snakes and ladders; or 

2. The first live radio commentary featured a Division One match between Arsenal and Sheffield United, broadcast on January 22, 1927. A grid of a football pitch divided into eight numbered squares had been printed in the previous week’s Radio Times so the commentator could describe the ball’s location. Square one meant the rear left quadrant of the defender’s side of the field.