If you opponent is in 3rd, find his sword on the inside using 2nd.
If you opponent resists the constraint, disengage under his sword while taking a step and mutating into 2-3rd. You will end up on the outside with your hand low and your point wide. This should result in an even stronger constraint.
Do not try to constrain on the outside using 2nd. It will be weak and ineffectual.
You opponent is likely to resist again. As he does so, disengage under his sword while taking a step and mutating into 2nd. You will end up on the inside hand moderately high and your more or less on line.
Continue is likewise manner, gaining more and more of your opponent’s blade until you are so close that you cannot miss.
Constant movement is vital. There are no moments of stillness, you must be slowly but persistently advancing. If you are not advancing and mutating, you are advancing and solidifying the constraint.
This has to consist of instinctive reactions to the opponent’s actions. Taking time to think means taking a tempo of stillness, which is very dangerous.
You can’t plan ahead. Opponent’s won’t react predictably and plans are likely to go astray.