The trail begins in the Selva di Filetto, in front of the San Genesio oratory. The first part of the track, up to the town of Batalasco, is shared with the orange trail 22. From Batalasco the route continues following the signs of the Via Francigena to the town of Fornoli. Once in Fornoli, turn left onto an asphalted road towards Cortonuovo and the locality called “La Conca”, where it rejoins the orange route 22, which will remain common until the crossroads for San Terenziano.
At the crossroads, the trail climbs up a forest road to the summit of Mount Barca, which is distinguished by the presence of a stone that recalls the names of some partisans killed by the Nazis. From the summit begins a steep descent first on a forest road and then a very demanding singletrack that leads to the village of Pastina.
From the small village you descend again first on the asphalted road and then the dirt road, until you reach the hamlet of the Bagnone Castle. The trail continues until it reaches the starting point, which it shares with trails 20 (light blue) and 22 (orange).