Why are the players from Real Sociedad called 'txuri-urdines'?

Real Sociedad is one of the historical teams of LaLiga. Together with nine more teams, it holds the honour not to have ever played below the category of Liga Adelante. Just as the rest of the teams, it has a particular pseudonym that describes its followers and football players.

As is the case for other clubs, language is a fundamental factor in creating its nickname. The donostiarra team is known as 'txuri-urdin', which in Euskera means blue and white, in reference to the colours that the team wears. For that reason, the football players that wear its shirt and their followers are known as 'txuri-urdines', a nickname that they take to all stadiums.