The traditional hand-mowing competition in Kupres is held every year on the first Sunday of July on the Strljanica Field located on the Kupres Plateau. According to available written records, this tradition has been recorded since the first decades of the 20th century. It is the most important social event in the wider Kupres region, participated by the best mowers, hosts and guests from other regions. The competition has strict rules and clearly defined criteria. It is visited and watched by numerous visitors, who encourage the competitors cheering loudly.

The Kupres Field has a very well developed livestock tradition, to which mowing is closely linked, i.e. collecting grass-hay in July for winter livestock feed. Mowing grass in folk tradition represents a skill and knowledge that boys and younger married men proudly demonstrate in the summer during a joint mowing, called moba. To achieve the best results in the competition, the scythes use hand-forged scythes, which are made in rare blacksmith shops today. Only scythes forged in this way are suitable for the demanding, sharp mountain grass of the Kupres Plateau.

The best mower receives the title of kozbaša, which he proudly holds until the next competition, which brings him honour and respect in society.

The custom of grass-cutting competitions on Kupres was inscribed on the UNESCO Representative List of the Intangible Cultural Heritage of Humanity in 2020.