摘要： Context. Over the last decade a large number of dusty star-forming galaxies has been discovered up to redshift z = 2 ? 3 and recent studies have attempted to push the highly confused Herschel SPIRE surveys beyond that distance. To search for z ≥ 4 galaxies they often consider the sources with ?uxes rising from 250 μm to 500 μm (so-called “500 μm-risers”). Herschel surveys offer a unique opportunity to ef?ciently select a large number of these rare objects, and thus gain insight into the prodigious star-forming activity that takes place in the very distant Universe. Aims. We aim to implement a novel method to obtain a statistical sample of 500 μm-risers and fully evaluate our selection inspecting different models of galaxy evolution. Methods. We consider one of the largest and deepest Herschel surveys, the Herschel Virgo Cluster Survey. We develop a novel selection algorithm which links the source extraction and spectral energy distribution ?tting. To fully quantify selection biases we make end-to-end simulations including clustering and lensing. Results. We select 133 500 μm-risers over 55 deg2, imposing the criteria: S 500 > S 350 > S 250, S 250 > 13.2 mJy and S 500 > 30 mJy. Differential number counts are in fairly good agreement with models, displaying a better match than other existing samples. The estimated fraction of strongly lensed sources is 24+6 Conclusions. We present the faintest sample of 500 μm-risers down to S 250 = 13.2 mJy. We show that noise and strong lensing have an important impact on measured counts and redshift distribution of selected sources. We estimate the ?ux-corrected star formation rate density at 4 < z < 5 with the 500 μm-risers and ?nd it to be close to the total value measured in far-infrared. This indicates that colour selection is not a limiting effect to search for the most massive, dusty z > 4 sources.