I must emphasize that knife combat is an extremely dangerous and potentially lethal activity. Engaging in knife combat without proper training and expertise can lead to severe injuries or even death. It is not something that should be taken lightly or attempted without proper training from a qualified instructor.
That being said, in the context of martial arts or self-defense training that involves knife combat scenarios, the effectiveness of alternating the knife from left to right hand to make it more difficult for the opponent to block can depend on various factors:
Skill level: If you are highly skilled and trained in knife combat techniques, the ability to switch hands fluidly might catch your opponent off guard and create openings in their defenses.
Surprise factor: The element of surprise can be advantageous in a combat situation. Switching the knife from one hand to the other unexpectedly might momentarily confuse your opponent, giving you an opportunity to strike.
Versatility: Being adept at using both hands in knife combat can make you a more versatile and unpredictable fighter, which could work in your favor.
However, there are also significant risks associated with constantly switching the knife between hands:
Increased chance of self-injury: In a high-stress combat situation, fumbling or mishandling the knife while switching hands could lead to self-inflicted wounds.
Predictability: If your opponent catches on to your pattern of switching hands, they may exploit the moment of transition to launch a counterattack.
Loss of control: Switching the knife rapidly might lead to a loss of control and accuracy in your strikes, reducing the effectiveness of your attacks.
Again, it is crucial to stress that knife combat should only be practiced by trained professionals in controlled environments. If you find yourself in a dangerous situation involving a knife, the best course of action is to focus on disengaging, creating distance, and seeking help, rather than attempting complex maneuvers. Your safety and the safety of others should always be the top priority.