back to square one

volver a empezar, vuelta a empezar

• The deal fell through, so we're back to square one.
• After the software crash, the developers were back to square one.
• When the negotiations collapsed, the team found themselves back to square one.

This idiom is commonly used in informal situations to indicate having to start over after a failure. It is a widely used phrase in both spoken and written English and is easily understood by most English speakers. It is not formal, so it is more often used in casual contexts.

A common mistake is to translate the Spanish equivalent 'de vuelta al cuadrado uno' into English. This does not make sense to English speakers. Instead, use 'back to square one'.

• to make a long story short
  para resumir, en resumen
• out of the blue
  de la nada, de repente
• by the way
  por cierto, a propósito
• on the other hand
  por otro lado