Grasping Weapon
You can use this weapon to grab targets, adding the weapon's enhancement bonus to your grab attack. You can still use this weapon to attack a target you’ve grabbed with it.
How does it affect the rules when on a weapon with reach?
Is it possible to grab somebody who is not adjacent?
If it is, can the holder of the weapon shift closer to his target?
Is it possible to grab somebody who is not adjacent?
If your natural melee reach is 1, then No.
GrabDDI explicitly states that you don't have to count the extra reach of a weapon, while a Grasping WeaponDDI doesn't define any exception to this rule.
This is somewhat reinforced by the Grasping Weapon encounter power:
Power (Encounter): Free Action. Use this power when you hit with the weapon. Pull the target 1 square into an unoccupied space adjacent to you. The target is grabbed (until escape).
It first pulls the target within melee reach in order to allow a "regular" grab.
If your melee reach is higher than 1 (Large or larger monster) then you can grab creatures not adjacent to you (so Yes).
Furthermore, with a Large or larger reach weaponDDI, you can target creatures one square beyond your normal melee reach. But still, you cannot initiate a grab at this distance (unless you are using the Grasping Weapon encounter power).
