The participating shops offer their clients a special pintxo snack which must be made with two ingredients proposed by their chefs.
This week event attracts all members of the public who want to enjoy a different culinary experience.
On the last day, a jury formed by professional chefs elects the winning pintxo.
The participants can also vote for the best pintxo by filling out ballots at the places where they are sold; they are thus eligible to win a weekend for two people at a very special place.
A draw is also held to award a meal at the winning restaurant for two of the participants with a comment published on the Facebook wall of Urdazubi/Urdax Dantxarinea indicating their preference for the winning pintxo.