yes!
i study two-handed/hand-and-a-half swordfighting, which is, no shield. so it is especially true about the techniques i have learned, that the sword is used to protect yourself just as much as it is used to attack your enemy.
and parrying is really even more important than attacking - it hardly matters if you are able to wound your adversary, if he also wounds you.
first protect yourself: get salvation.
second, look for openings to riposte. put to death the sinful desires of the flesh. that's the order. you cannot win a battle by only blocking, but you cannot survive a battle if you never block.
the medieval sword masters are not in unanimous agreement about whether to block with the edge or the flat of your blade. some prefer one, some prefer the other, and some seem to use the edge to block in some contexts and the flat in others. i'm not really clear about how that translates to spiritual metaphor?
but i can tell you this: there are three primary ways to parry.
first, you can hold your sword firmly in the way of the opponents weapon, like a wall. you do this with the part of your blade close to the hilt, called the 'strong' of the sword.
second, you can cut into their cut at the same time they are cutting, so that you either knock their attack out of the way as you follow through, or at least keep him from being able to complete his attack. you do this with the center of percussion, for most swords about 2/3 of the way towards the tip. that's the part that transmits the most force when you swing, identical to the 'sweet spot' on a baseball bat.
and third, you can use the tip of your blade to deflect the adversary's blow. you only have to move his weapon a little bit in order to keep it from landing where he wants it to land, but to do this you need to act very quickly, anticipating his movements, so that you contact his weapon just after he begins to strike. the tip of your sword is called the 'weak' because it has the least leverage, and if you are too late in trying to deflect, you won't have the strength to move his strike far enough to keep you out of danger. you do it early so that your 'weak' contacts his 'weak' instead of his 'strong'
so the easiest parry is to bring your sword up like a wall. this takes strength, but it doesn't take so quick of a reaction time.
the middle parry is to respond to his attack with a similar attack of your own, aiming at his own weapon. this takes quicker reflexes but it's more natural to do, in a sense, because it's the same general motion as making an attack of your own.
the hardest thing to do requires the least strength but the greatest skill & speed - to use a small motion at just the right time to make his attacks swing harmlessly through the air. this in turn gives you the best chance to counterattack