What Tobi says PLUS there is more…
It’s not fully working yet (at least in the Alpha build) but position of your sword is actually (somewhat) important in a parry. I wouldn’t call it a directional blocking but if you copy enemy’s sword position, it’s easier for you to make a parry (timed block). It’s just a matter of physics: sword needs to travel shorter distance, hence more forgiving timing (once you press a parry too late, the distance actually matters, so if you are attacked from above and you have your sword down on your right side, you will not make a parry in time and get hit). Timing is still more important: if you press the block in perfect time, you will always parry, regardless your sword’s position (well… except it’s in the scabbard or in a liver of some other enemy), however having your sword closer to the attack means the timing is more forgiving (not that much, but still…).
As I’ve said: it’s not much working in the Alpha There were some serious troubles around it, will be fixed in the next one (hopefully).
Of course “historical” part in the combo is only the final strike. The combo itself just provides a way how to “adjust” your opponent for this strike. Like slashing from the upper right will get him to a position when he is expecting the strike from lower left and you can come with an unexpected short-edged strike (just an example). Also, it’s a “gamy” way how to even initiate these techniques, what you need when you have just two mouse buttons…