Plate

Both fencers inside in Third; enemy passes left foot with Second over sword; striker lowers point, hand in Fourth, turns body to meet the flank
Both fencers inside in Third; enemy passes left foot with Second over sword; striker lowers point, hand in Fourth, turns body to meet the flank De lo Schermo, overo Scienza d'Arme · Copenhagen, 1606 · Plate 55

Translation

This wound in Fourth against a Second may occur in two ways. The first is that both combatants are in Third on the inside, and the striker goes to find the enemy blade, while the other disengages in Second over the enemy sword and passes beyond with the left foot. The striker lowers the point without disengaging (abbassando la punta senza cauare), leaving the arm somewhat angled inward, as is seen, and the hand in Fourth; and by turning the body with the left foot he meets the enemy as he comes and wounds him in the side under the right arm. Thus the enemy sword passes empty and without touching.

The second way is that the striker has disengaged to the outside, and the other tries to take that time in order to wound above in Second. Then the striker does nothing but lower the point, which had gone to the outside, under the enemy blade, leaving the hand in the same place but turning it into Fourth, and without extending the arm turns the body, removing from presence all that part which had been uncovered in guard. This play therefore belongs both to the family of under-the-sword actions and to the family of passing or turning responses to Second.

Analysis

Initial guards Both in Third on the inside; alternate starts after you disengage outside.
Wound Thrust in Fourth to the flank / side.
Version 1
  1. You go to find the enemy blade.
  2. He disengages in seconda over your sword and passes with the left foot.
  3. You lower your point without disengaging.
  4. You let the arm angle inward.
  5. Your hand remains in quarta.
  6. Turning the body with the left foot, you meet the incoming enemy.
  7. You hit him under the right arm / in the side.
  8. His blade passes empty.
Version 2
  1. You disengage outside.
  2. He seeks to take that time with seconda above.
  3. You do nothing but lower the point, now outside, under his sword.
  4. You keep the hand in place but turn it into quarta.
  5. Without extending the arm, you turn the body and remove the exposed line from presenza.

Translation note

This is not just "another Fourth against a Second." More exactly: against a passing or overpassing Second.
The Steel Marginalia · HEMA Study Group Notes in the margins. Truth in the bind.