in the ossenheim exhibition hall, the gallery is showing reiner kallhardt's architectural sculpture "harmonie". an urban plan based on the magic square – a mathematical discovery of a sequence of numbers whose traces were found in china around 2,800 years bc. reiner kallhardt has built a model that transforms the surface equality of the shapes in his pictures and thus the possible color equality from the 2-dimensional, the surface of the picture, into the three to four dimensional of the volume equality of bodies, here houses and a city model. it could become a venue for the art of the world, a meeting place for artists of the world. this city forms the place, real and digital, to create, to present what has been created, to show and develop visions, a place for logics, debates, solutions, differences, with the desire to recognize these as diversity.

the starting point for the model is the concept of the 'harmonic square.' 9 squares of equal size form the structure for the base of the architectural sculpture. each of these 9 squares is in turn divided into 9 sub-squares. each of these 81 sub-squares is divided into 9 concentric square rings of equal surface area. in the system of this magic square, a chessboard-like structure, the numbers 0 to 9 are arranged in such a way that each row and each column as well as the two diagonals add up to the same sum. each number in turn stands for one of the concentric square rings or fields.

just as the concentric rings have the same surface area, the architectural bodies have the same volume. based on the principle of equal volume. all the compositional sequences visible in this pictorial plan follow the laws of the harmonic square and, analogous to the numbers, each volume occurs only once. two architectural models are shown: the initial square with nine sub-squares on a scale of 1:1000 (81 x 81 x 27cm) and a selected, more detailed sub-square on a scale of 1:100 (270 x 270 x 270cm). a video on the development of the system is on view as well.

in addition to "harmonie," the gallery shows works, numbered and signed multiples, and prints from the series of 'multivariable systems' by reiner kallhardt. these are equally based on the magic-square-principle and its two-dimensional surface equality. these works date from the beginnings of edition hoffmann activities in the 1970s. for the presentation, reiner kallhardt has developed a conncept for a nine-part portfolio "nonnet."

we are looking forward to reiner kallhardt, the artist and great exhibition organiser. together with dietrich mahlow, he curated the biennial "elemente und prinzipien" in 1969. in this context, edition hoffmann realised the first portfolio "gruppe bewegung" by an artist collective from russia. we are also looking forward to one of the "uncomfortable" members of the group "kassler konkrete". we are looking forward to meeting him as the initiator of peter volkwein's endeavour to found the 1st museum for concrete art in ingolstadt. we are excited to hear about his life as an artist and professor in china and now back here, as an artist in cologne. we look forward to meeting you, the members of the audience, perhaps in expert discussions with the artist, you, the architects, urban planners, the city administration and utopians in general!

hanna sturm and jörg sturm (architekturbüro sturm und wartzeck) will be in conversation with reiner kallhardt at 4 pm. we invite you to join us!