Tempo and Indes, In Theory
Consider the fight between a fencer in vom Tag against a fencer in Alber
In the fencer in vom Tag commits to an attack, the fencer in Alber, can counter to leaping forward and slicing the wrists. Or springing to the side and throwing a descending crooked cut to the arms. Or by beating the flat or short edge of the incoming sword with his short edge, then attacking the opening from which it came. Or by stepping forward with a crown cut that ends with a downward thrust, a short-edge cut, or a pommel to the face.
In the fencer in Alber commits to an attack, the fencer in vom Tag steps to the side and cuts his arms from above. Or leans forward while throwing his hips back to overreach.
If either fencer takes an unnecessary step, or shuffles his feet to settle into his guard, that’s a commitment to footwork that the other fencer can take advantage of with a quick, direct strike.
If either fencer feints and his opponent ignores it, that is a commitment to inaction and the feint is turned into a real attack. (All feints must be convertible into real attacks or they are just wasted movements.)
If either fencer feints and his opponent commits to the parry, the feint is changed into a different attack so that the parry is wasted. This could be a thrust into a cut, or a cut into a thrust, or either being sent to a different opening than originally planned.
Tempo: Each action, or inaction, creates a tempo (i.e. period of time). And if the other person acts correctly, a new tempo is created and any further commitment to the original action by the first fencer is wasted. But if the first fencer was not overly committed to his action, he can create a third tempo and regain control of the fight. In short, the last person to make a correct decision wins.
Indes: Each step, each cut, each thrust, each wrestling, they all have numerous decision points. Moments where you can choose to continue the action, abort the action, or transmute it into a different action. Indes is the ability to instantly recognize these decision points, correctly assess the situation, and change your action accordingly. Each time your opponent chooses to change his action, or chooses to do nothing, you need to change your action as well in order to control the fight. In short, the last person to make a correct decision wins.
Tempo and Indes, two ways to explain the same basic concept of not overcommitting to an action and paying attention to when the situation changes.
Tempo and Index, Applied
When reading any technique or play from a manual, or watching any presentation or video on the same, always be willing to ask the question, “What if he does something different at this point?”. The plays rarely discuss all of the correct decisions that can be made by your opponent, and they never cover all of the incorrect ones. Given the limitations of page space, they cover either the most likely response or the correct response that is hardest for you to counter.
So I is up to us to consider each moment of indes carefully and to investigate the tempi can arise from it. We can’t disregard a possible response just because it wasn’t covered in the particular manual we are looking at, for there is no guarantee that our opponent will do the same. No, we can only disregard a response when we know for certain that it cannot harm us or if we get to the point where we can instinctively counter it without thought.