Guard Switching (also known as Rhythm Blocking) is an option select where you guard one direction for a set amount of time, then change directions. This takes advantage of the timing differences between the two attacks and guards against both of them - by blocking in one direction, then switching to the other.
- The opponent performs a crossup
- You recognize this setup and understand that this particular crossup only happens after a set amount of time - if the opponent attempts to hit you before then, then it is not a crossup
- You block one direction () until the crossup would appear, and then switch to blocking the other direction ()
- The opponent performs a jump-in
- You block high until the overhead would appear (ie while they are airborne), then switch to blocking low immediately when they land.
- Mid-Blockstring Overhead
- The opponent does a blockstring, the next hit can be either high or low, but the overhead is slower than the low.
- You block low until the overhead would appear, then switch to blocking high.
- For example, the low would hit in 12F, and the overhead would hit in 25F. You can block low, then switch to high after 12F to block the overhead high.
By changing the direction you block not based on reactions, but on a set timing, you can guard against both situations without worrying about which way the opponent will attack.
Defending against this kind of crossup requires you to recognize the situation and change your blocking direction at the right time. The opponent can play around your expectations by going for different crossups with different timings or ways to block!
This same principle can also be applied to high/low mixups like basic jump-ins (~).
Since Guard Switch is on a set rhythm, players who recognize this can try to do mixups that don't follow that rhythm - just delay attacking slightly and you can hit them with seemingly easy to block mixups like Low attack > delay > Low attack!