Now we’ll have a look at the cordon – that means a line or chain of black warriors, which ideally will sweep across the board like a line of policemen searching for an escaped convict, eventually trapping the king. This is black’s next concern, after securing the corners.
The arrows show the desired progress of the black cordon across the board, gradually reducing the territory controlled by white. In practise it is rarely as simple as this, because white will attempt to slow down or disrupt the cordon.
Black must take special care when moving a cordon across the throne square, because of the danger squares next to it.
Notice that there are no white warriors behind the cordon! Even one white warrior on the wrong side of a cordon can fatally weaken it.