III. This is located by the crimp

When the riffle is used, the crimp is put in by first concaving the whole deck. This is a natural procedure, as the cards have a tendency to get convex, and it is quite customary for the players to straighten them up. By drawing the deck to the edge of the table the concave tendency can be put in the whole deck first, then as the extra cut is made a convex crimp can be put in the under part by pressing it quickly downwards with right thumb against the table edge as it is drawn out. The ally cuts by the ends.