Press when the blow lands
Not when you think you should parry — when it actually lands. The lead is arithmetic and this page can do it for you; what it cannot do is guess how far apart your presses fall, which is the half that decides everything. 8 attempts before the numbers mean anything, and the swing is a different length every time so you cannot count it.
Press when the blow reaches the line.
Save the numbers to your private Device Passport in this browser, or copy a card that shows exactly what was measured.
Nothing is uploaded unless you contribute. Cards and links contain only the numbers shown above.