The Basque derby (in Basque Euskal Derbia, in Spanish derbi Vasco) is the name of the football local derby between Real Sociedad and Athletic Bilbao. It embodies the inter-city rivalry between Bilbao and Donostia-San Sebastián, capitals of the neighbouring provinces of Gipuzkoa and Biscay (Bizkaia) in the Basque Country region of Spain. It is also occasionally referred to as the AP-8 derby, referring to the name of the highway which connects the cities.
Background
The derby was first played in April 1909 and has attracted the attention of local football fans ever since. These two organisations are the largest football clubs in the Basque Country and have stayed in the top division of Spanish football for longer than most clubs, winning several trophies in the last hundred years. Both enjoyed a period of great success in the early 1980s, winning four national titles in succession between them, whilst using only local players.

Other clubs in the territory have also competed in the top division (and opposed Real Sociedad occasionally in the second tier, in addition to cup ties), with CA Osasuna, Deportivo Alavés, and SD Eibar the most prominent of these; the matches between any of them are also referred to as a “Basque derby”.

Supporters of both teams traditionally mix in and around the stadiums on matchdays, somewhat unusually for a local derby, and take part in organised accompanying events such as a 'kalijera' (a supporters' parade from the city centre to the stadium) and the 'Bertso-derbia', a singing and poetry contest between the two groups in the style of the traditional Bertsolaritza. The fans have received praise for the relaxed atmosphere which usually accompanies the derby matches, and although incidents have occurred within the stadia, the hostility is usually directed towards rival players rather than fans.

Real Sociedad has played in the second division for some short periods of its history (16 seasons, the longest spell being five years) and for that reason the derby has not always been contested every season. Athletic Bilbao has never been relegated, meaning all their league matches have taken place in the top tier. In the 21st century, there has only been one enforced break in the fixtures, a three-year (1400 days) hiatus between January 2007 and December 2010.
History
1900s cups
The first meeting between Athletic Bilbao and a team which evolved into Real Sociedad should have taken place in the 1905 Copa del Rey, which consisted of a mini-league with just three teams: Athletic, hosts Madrid F.C. and San Sebastián Recreation Club. After Madrid defeated both Basque teams, Athletic declined to play the dead rubber between them. Despite this withdrawal, however, the federation considers Athletic to be the runners-up in the tournament as it was their match with Madrid which confirmed the latter as the winners.
By the 1909 event, the Recreation Club had evolved into San Sebastián Foot-Ball Club but aligned with Club Ciclista de San Sebastián to meet the entry requirements. They defeated Athletic in the opening round and went on to win the trophy.
The following year, the club was renamed Sociedad de Foot-Ball de San Sebastián and had received royal patronage, entitling it to add the prefix Real. However a dispute occurred over the entitlement of Real Sociedad to claim the honour of champions, and two separate competitions were held (both of which were later declared official, meaning there are two 1910 winners). Although Real Sociedad hosted their version of the competition at their Ondarreta ground, once again they did not meet the requisite statutes and their players joined with another club to participate, this time Vasconia Sporting Club. Once more it was a three-team league involving Athletic Bilbao and Madrid, with Athletic winning both of their matches to win the cup, with the decisive win being over Vasconia who are thus listed as runners-up (and in any case they beat Madrid to confirm that status).





