Chess in Madrid you can simply turn up to 6

These are the entries whose sources say outright that anyone may come. On Friday evenings Academia de Ajedrez Chamberí hosts an open get-together, the same one that the Madrid Chess Meetup group announces, and Octava Casilla in Hortaleza opens its club evening to non-members. Gambit Café in Malasaña is a café: you walk in and take a board.

In Chamartín the district council runs Ajedrez en los parques, sessions led by a monitor with no registration, on Friday afternoons in the Jardines de Pablo Sorozábal and on Saturday mornings in the Parque de Gloria Fuertes, from spring to late autumn. The list is short because it holds only places where a page states the open door; many clubs may well receive visitors, but their sources do not say it.