Four crossings drill
This drill establishes the four most critical (because hardest to distinguish) crossing conditions, all of which happen middle to middle.
From the perspective of the one who executes the plays:
1: sword goes wide: which leads to the 2nd play of the second master of zogho largo
2: sword stays close, no pressure in the bind: 3rd play of the second master of zogho largo
3: swords are close, some pressure in the bind but inside line stays open: 2nd play of the master of zogho stretto.
4: swords are close, more pressure in the bind, closing inside line and opening the outside: 3rd play of the master of zogho stretto.