Double crosscut to connect
This is the abstract form of the connection. The marked stones indicate the two crosscuts which connect the unmarked stones and the groups they belong to or areas they influence a and b. Each of the four stones, when absent, indicates the only move with which the connection can be ensured.
Symmetry aside, Black's only other move is the empty triangle which is obviously caught.
This is a related technique IMO tderz.
and the induced can be interpreted as having the same constellation as above.
White induced the kosumi-crosscut. (source: from the 'kiri' section of Go Seigen's Tesuji dictionary)