First line capture
The first line capture is one of the basic edge patterns. A fanciful name for this pattern is the grotto.
This method does not work if there is a friendly stone (square) to flee toward. However, the stone can still be caught in a net as below. In this variation, the cutting point at a must be be protected...
Otherwise, White cuts with 1, and the capture will go the other way!
tapir: Isn't white dead even after capturing on the first line?
However, beware of the special properties of the corner!