What critical feature must the Welsh Terrier's tail carriage avoid?

Answer

Curving over the back in a tight curl.

The tail carriage is a distinct element of the breed’s alert attitude and proper outline. While the tail is set high on the back and should traditionally be carried cheerfully erect, there is a strict negative requirement: it absolutely must not curl tightly over the line of the back. Historically, tail docking was sometimes performed to ensure the tail retained the correct carriage and helped balance the dog's overall square appearance. Regardless of docking status, preventing that tight curl above the spine is mandatory for correct presentation.

What critical feature must the Welsh Terrier's tail carriage avoid?
appearanceDogmorphologyphysical characteristicWelsh Terrier