What exactly is 'Impetus' in the rules? Do you throw extra dice in the openeing occasion of each type of close contact? Page 38 - 7.4 explains it as a modifier or number of dice..............how do I know which it is? love the game so far but this is rather spurious.

Impetus is a bonus number of dice given to a fresh unit charging in the first turn of melee, or in subsequent melees following contact after a pursuit.
Defending units, and worn attacking units and units already in melee do not get the Impetus bonus.

Hope that helps.