The stretch starts from the crossroads for Secciano, Calenzano, and goes up to the Croci di Calenzano.
The first part, on asphalt, has slopes with peaks of 21/22% on average around 10/12 for the entire asphalted part.
Then at the last beautiful farmhouse you continue on a dirt/paved road but, with dry ground, you can do it without setting foot on the ground. The path/road is always wide and intuitive even if it has a couple of crossroads that can be misleading.
Along the dirt road there is a well-marked crossroads that leads to Valobona, a small uninhabited village where the, unfortunately famous, massacre by the Nazi-fascists took place!
Continue without turning along the dirt road for a couple of km and then return to the asphalt road up to the Croci di Calenzano.