Condottiere
Emperor Mongoose
The centre of gravity in a castle tends to be the main gateway, which is why they're heavily fortified and reinforced in later renovations, or built that way from the ground up.
In Traveller, it would have to be a system whose occupation or control gives access to the hinterland, or allows a task force to jump to another system that would permit a breakthrough.
In Traveller, it would have to be a system whose occupation or control gives access to the hinterland, or allows a task force to jump to another system that would permit a breakthrough.