Retno Bieg is a small forest race held in Czystebłota, near Pokrzydowo in Poland’s Kujawsko-Pomorskie region. It provides 5 km and 10 km distances. The 5 km option accommodates both running and Nordic walking, and the race employs electronic timing, distinguishing it from a casual fun-run format.
The race headquarters, start, and finish are located at Hotel Pory Roku in Czystebłota. The 10 km course follows a cross-country path connecting Czystebłota, Zastawie, and Lipowiec before returning to Czystebłota. The 5 km route remains within the Czystebłota forest. Both courses are marked, with water stations available on the routes, and all participants completing the race receive a medal. The organizing bodies include Hotel Pory Roku, the cultural and sports center in Zbiczno, Powiat Brodnicki, SieBiega Association, and CBR Biega.