In his study entitled A magyar népzene [Hungarian folk music] and released in 1937, Kodály already discussed the stylistic layers of folk music on a historical and comparative, i.e. on a philological basis. He repudiated Bartók’s plan for a complete edition because he found it necessary to develop other principles, closer to the dictionary-like disposition, for the classification and publication of the collection which was rapidly increasing during the post-war period. However, he did not engage in the development itself, instead he left it in the hands of his disciples to classify his record cards stored in a mechanic system. It is for this reason that we cannot speak of a genuine “system” established and sealed by Kodály. The collection was designated as the Kodály System by the posterity.

The collection consisting of approximately 33,000 master sheets/record cards, similarly to the Bartók System, is a part treated as a closed unit of the folk music collection of the Institute for Musicology.

The data entry, the verification, and the unification of the Kodály System are still in progress. At present, the digital copies of the master sheets/record cards can be browsed and the first part of the collection is searchable by text incipit under