The Blade Dodge Takedown is a Takedown in Batman: Arkham City onwards, in which an enemy launched a series of attacks with a blade or sharp object, each of which was dodged by the character performing it before he delivered a devastating blow that immediately leaves them unconscious.
The Blade Dodge Takedown can be difficult to master. Most players probably just tap the counter button, which makes it even harder to pull off consistently, while the key to doing it is to hold the button and release it after each of the enemy's swipes. Try to learn the simpler Blade Dodge first.
The Blade Dodge Takedown adds 3 multipliers to the combo meter and 100 points for every multipliers (more than any other attack, except the Titan Takedown and Environment Takedown.
The Blade Dodge Takedown does not destroy an enemy's blade or bottle. When the enemy is knocked unconscious, their weapon merely fall to the floor, where another enemy could pick it up and use it. Consider using Special Combo Disarm and Destroy to destroy an enemy's weapon for the duration of the battle.
The Takedown requires better timing in Arkham Knight than in City or Origins. A Blade Dodge Takedown can be used against a brute with blades, although it results in a mere Instant Takedown (with 50 points for each multipliers in combat challenge maps); an armored brute requires two takedowns to be completely knocked out.
The Takedown can be used on any type of enemies with broken bottles or sharp blades (thugs, ninjas/combat experts, brutes, except Sickle), but also on Copperhead in Batman: Arkham Origins as she attacks with her sharp fingernails.