When a unit moves; does the unit leader have to reach base contact to start a melee, or can a model be placed in cohesion and in base contact with an enemy unit?

1 hour ago, lologrelol said:

When a unit moves; does the unit leader have to reach base contact to start a melee, or can a model be placed in cohesion and in base contact with an enemy unit?

The leader must reach base contact with an enemy model. Cohesion does not work.