As seen here, Musashi’s thoughts on Timing/Interval (Hyoshi) and Distance (Ma or Maai) are pretty complex. But what is clear is that he taught that issues in combat arise when our awareness lags behind physical movement, producing a disconnect – dead time or Kyo in us or in the opponent. In Musashi’s day, a Samurai in combat who changed his facial expression slightly opened him up for attack, as it was seen as a pause in his defenses.
For me, transition between movements is a weakness: a slight front foot shift before an attack, or slight posture changes when switching stances, often open up a space when an astute opponent can attack.
A common thought is that if your opponent’s reach isn’t as good as yours, you need to initiate the offensive, and conversely, if your opponent is on the offensive, you need to utilize your defense and counterattacks. Either way, understanding timing is the difference; understanding where dead time exists and being in a position to cover the distance to take advantage of it, or to shift adequately to take away his action space or to parry the attack.
The bottom line: My Hyoshi and Maai need a lot of work!