Establish the context
Identify the weapon, the fencer on each side, the score and the stage of the event. Camera direction can change between recordings. Write down which side your athlete occupies rather than relying on the colour of a light.
Watch a complete phrase
Begin before the final action. Notice how the distance changes, who creates an opening, and what happens before the halt. Then check the referee’s decision and the scoreboard. In foil and sabre, right of way needs more context than who seems to move first.
Write a question, not a verdict
If the blade or scoring box is out of frame, mark the moment as uncertain. A useful note is “At 00:42 the back foot reaches the line; did that limit the next retreat?” Keep the timestamp so a coach can see the same evidence.