Results of the LHCf experiment and the forward measurements at the LHC

The Large Hadron Collider is intensively used to test hadronic interaction models used in cosmic-ray physics because its maximum (designed) collision energy √ s = 14 TeV corresponds to the interaction of a 10 17  eV cosmic-ray proton hitting the atmosphere. In this paper various types of forward experiments at the LHC, where the particles relevant to the air shower development are observed, are reviewed. Recent results of a dedicated experiment for precise forward measurement, the LHC forward, are discussed in detail. A future possibility at the LHC, light ion collisions, is also discussed.