The collection housed in the Oteiza Museum contains 1,690 sculptures, 800 drawings, 2,000 chalk laboratory studies, about 5,000 books from his personal library, as well as his extensive newspaper and periodicals library and his countless writings that are still being catalogued.

The collection in Alzuza has some highly significant pieces from all the sculptor’s creative periods and makes it possible to offer a comprehensive overview of the artist’s various concerns and sculptural practices, which were closely linked to the development of the aesthetic languages of art in the XX century.

His legacy begins with a display of his early figurative and expressionist creations from the beginning of the 1930s. This body of work also contains numerous pieces produced after the artist’s return from South America in 1948, such as some ceramic pieces and work that gradually abandoned any figurative features and progressed in the process of emptying and vacating the mass towards a vertical, light and lightweight type of sculpture, which the artist himself called “trans-statues”.

The collection also contains numerous pieces that formed part of the project for the sculptures in the Basilica in Arantzazu, some of his portraits, as well as the pieces that show his research with what are known as light modules, in which the light element becomes a key part in the research and treatment of the spatial projection of sculpture due to the absence of mass. The collection continues with numerous studies of the “functional extension of the wall” connected with his mural relief work and contains essential pieces in the series of twin crystals and openings in polyhedrons as examples of his formal research on the effects of the dynamic action of hyper-space on sculpture.

The creative legacy that the Oteiza Museum preserves continues with the pieces linked with the successive processes of emptying and vacating geometrical forms (cube, cylinder, sphere), many of which formed part of the Experimental Proposition 1956-1957 which won the Grand Prix for Sculpture at the Sao Paulo Biennial.

This overview is finally rounded off by the pieces that concluded his experimentation: the metaphysical and empty boxes, in which the artist’s spatial treatment of sculpture resulted in his abandoning sculpture, once he had brought his experimentation to a close, rejected the production of further variants and stated that “I ended up without any sculpture in my hands”.

A key element in this collection is the so-called Chalk Laboratory, which consists of chalk, paper, brass, plaster, wood and cork pieces, with which the artist continued his plastic research after considering that his Experimental Proposition was over in 1959.

This experimental series is completed by sketches of relief work for mural projects and architectural interventions, as well as the glass models for studies of the Wall-light, which are unique pieces that are extremely important, singular features in the collection. These complete the collection of drawings and collages.