Shadow Matter is relatively hard to come by. You usually get them either by chance, or by buying it.
Farming for it is different matter.
You can only farm them from Boxes which are usually located in the center of the map or near it. The problem is that CHN and ZTT are protective about it. They WILL attack the tile just to evict you - and they mean business. Someone will attack you, who's way stronger.
TIP 1 - be discreet
- occupy the closest to you
- avoid intersecting lines
TIP 2 - be wary
- once occupied, don't leave it be.
- be ready to bug out when you get attacked
TIP 3 - don't be greedy
- if you have to leave, take your troops with you
- always assume that the attacker is way bigger and better than you