The OHO Group, a Slovene artistic collective formed in the late 1960s, consisted of Milenko Matanović, David Nez, Marko Pogačnik, and Andraž Šalamun as the permanent, core members. Other artists, for example, Tomaž Šalamun, who is well known as a poet today, often contributed or acted as part of the group. The OHO Group belonged to a wider Slovene intellectual and artistic circle called the OHO Movement and regularly collaborated with its members.
Igor Zabel on OHO
A particularly important phenomenon in the second half of the 60s and early 70s was the avant-garde group OHO. The development of the group can be divided into three rather different phases. The first was centred around the notion of Reism (from the Latin word „res", i.e. „thing"). The members of OHO wanted to develop a radically different relationship towards the world: instead of a humanistic position, which implies a world of objects dominated by the subject, they wanted to achieve a world of things, where there would be no hierarchical (or indeed any) difference between people and things; the correct relationship towards such a world is not action, but observing. OHO used a number of media (and their in-between forms), drawings, photographs, film, video (the first video works in Slovenia were produced in this context by Nuša and Srečo Dragan), music, texts, but also the way of dressing, living and behaviour, to redirect the awareness of people into Reistic observing. It is clear that they criticised the traditional division between art and life (they wanted to deprive art of its aura and to enter every-day life with small products, sometimes sold on the streets – such as matchboxes for which they produced several series of labels and which were sold simply for the price of a matchbox), as well as the idea of the creative personality (they tried to substitute the artistic will and deliberate procedures with accident, absurd or pre-determined mathematical programmes). In the second phase, the group established a dialogue with the contemporary artistic avant-garde: the artists used the principles of Arte Povera, Process Art, Land Art, Body Art and Conceptual Art. It is interesting, for example, to observe the opposition between the American Earthworks and OHO Land Art works: these were small-scale, ephemeral, done with simple tools in a cultivated landscape, and often very minimal, mild and poetic. Such a relationship was one of the starting points for the third phase of OHO’s work, which represented a combination of Concept Art and a kind of esoteric and ecological approach. The subject of the work was a harmonic unity between the members of the group, but also of the group and nature and even the universe as a whole. In the search for such a harmony, they used different means, including telepathy. The group was just starting an international career when the members decided they should abandon art as a separate area and really enter life; therefore, they settled on an abandoned farm and started a community.
Source: Igor Zabel, "Art in Slovenia since 1945".
- Grupa OHO, 1966-1971, Belgrade: Muzej savremene umetnosti, 1979,  pp. With text by Tomaž Brejc. (Serbo-Croatian)
- Groups Gorgona & OHO From Yugoslavia. XVI São Paulo Biennial, 1981. (English)
- Ješa Denegri, "Primjeri konceptualne umjetnosti u Jugoslaviji", Život umjetnosti 15-16, Zagreb, 1971, pp 147-152. (Serbo-Croatian)
- Igor Zabel, et al., OHO: Retrospektiva/Eine Retrospektive/A Retrospective, Ljubljana: Moderna Galerija, 1994, 120 pp; new ed., Ljubljana: Moderna Galerija, and Frankfurt am Main: Revolver, 2007, 167 pp. Exh. held at Moderna galerija Ljubljana, 1 Feb-13 Mar 1994; Neue Galerie am Landesmuseum Joanneum, Graz, 18 Aug-18 Sep 1994. (Slovenian)/(German)/(English)
- Miško Šuvaković, Skrite zgodovine skupine OHO, Ljubljana: P.A.R.A.S.I.T.E., 2009, 144 pp. Exh. held at P74 Center and Gallery, Ljubljana, 23 Apr-21 May 2009.  (Slovenian)
- The Clandestine Histories of the OHO Group: A Cold War Era Transgressive and Subversive Artistic Practice; Transgression, Sexuality, and Politics in the Pursuits of the OHO Group and the Movement OHO-Katalog, 1965-1971, trans. Irena Sentevska, Ljubljana: P.A.R.A.S.I.T.E., 2010, 149 pp.   (English)
- Beti Žerovc, "The OHO Files, Updated", ArtMargines, 15 Aug 2013. (English)