You don't need a partner to do longsword drills. Joachim Meÿer gives us a wonderful tool which we can use to create a large amount of useful drills.
The Meyer Cutting Diagram, aka the Meyer Square.
The numbers create a sequence, their position mark an opening. Cut at a number and move to the next.
Looking at the outer sequence, 1 marks an opening on their upper left side (your upper right), the next is the exact diagonal opposite, their lower right. Next go opposite but not diagonally, their lower left and finally the last opening at their upper right.
Here is some of the translated text:
"step and strike first from your right against his left ear, as soon as the strike hits on, then quickly twitch to fly off again, and strike the second from below diagonally against his right arm, however in this strike keep your cross high over your head, and step to him with your left foot a little to his right together with your strike from below, and hit on with this as well, should you nimbly move your sword over you to your right, and thus from your right strike to his lower left opening, as the right is pulled or hit then twitch off again to over your head, and strike the fourth seriously against his right ear, from then traverse over and pull out. The first four Strikes shall be nimble and quick from one opening to another for your steps to be successful."
You will note in the second strike Meÿer tells us to keep the hands high, this is done to maintain a defensive position as the other person is likely to strike back at us.
The diagram trains us multiple skills:
I'll write a number of drills you can do and get back to the concepts at the end.
For clarity, I've made this color coded diagram which divides the original diagram into clear squares. The diagram was inspired by one Keith Farrell had all I did was to add color coding to help distinguishing the sequences during workout.
If you like, print the file and use it in your training.
Pick a single sequence and work your way doing the 4 cuts involved. Iterate, then alternate. For simplicity, start with long edge cuts only.
Think of each square as a way for you to engage. You enter the spar and attack at an opening, then immediately work to the next opposite opening, and the next, then with a step out attack at the last opening to give you safety in the retreat.
Now that you are striking at the openings, add footwork to it.
Strike at an opening, then attack at the next, but before you connect, let your strike fall and move on to the next opening.
This has a powerful psychological effect. The person may be going to the position to meet your blade and subconsciously they will wait for the pressure signal before moving on. This may allow you to gain a free hit elsewhere.
Alternate when you pull the attack. Sometimes the second, at times the third. Work through pulling a different number each time, and sometimes pull twice in a sequence,
Cut to the same opening twice before moving to the next one. This will teach you more ways to come around with the sword and is overall a useful skill to have as people tend to move away from their openings, especially if there is a feint or pull involved.
Example with pulling:
It is also useful to do the entire square attacking each opening twice as it will teach you many movements.
Do your square with long edge cuts only. Work your way around to cutting through the guards and getting the long edge in.
Now replace the long edge with short edge cuts. Find new ways to move and to power your strikes.
Meÿer says you should be able to cut with the long, short and flat.
The reason behind it is that at his time fencing was a sport with fights lasting until one drew blood. Their swords were somewhat flexible which meant that cutting with the flat had a rebound effect when parried strongly, causing the tip to flex towards the target and possibly drawing blood. Meÿer seemed happy to game the system.
Personally, at time of this writing, I don't feel that cutting with the flat is overly useful in our modern HEMA environment as some places tend to discount hits with the flat and our rules and safety gear are quite different compared to Meÿer's time. That said, I am always happy to train more skills, so ¯\(ツ)/¯.
Now that you have done strikes with your long edge, short edge and possibly the flats, starting mixing them around. The number of possibilities to work through will leave you with much to do.
Can you do the square with the Zwerchau all the way around?
Every now and then transform your strike into a thrust. Perhaps cut and drive in the point after your cut, or maybe simply thrust.
So far we've been focusing on a single square or sequence. Now work your way from the outer square to the inner square.
You can also work your way from the inside to the outside, and if you are really hard working, mix them all up.
Let's be honest here: your very first cut was probably from Vom Tag or Ox on your right. Can you strike their upper left opening with strength from your left Plow?
Of course your attack will have less power, but can you do it? Meÿer says you should be able to. Get back to work!
Work the entire diagram in any order with the long edge and the short, and the flats and with pulling and with striking to the same opening twice.
Find where are you tells, make sure you are moving your sword before your body. Eliminate any useless motion.
Let's review some of the concepts these drills give us.
Meÿer says that when you attack at an opening, if they meet you, they are likely to be open at the opposite opening. This is why we attack crosswise, but not always diagonally.
We are told to keep attacking and move fluidly from one opening to the other. This exercise helps create that rhythm and the muscle memory to do so.
It is important to move side to side and not back and forth.
Moving to the side gives us an angle at the opponent that maintains the distance for us but puts them offline and shortens their reach (unless they pivot), this is basic Pythagoras Theorem.
Attacking at an angle in which your opponent is offline also puts them at an unfavorable position to parry it, which also limits their ability in performing their plays.
In addition to the angles and gained advantage, combining this with moving behind your sword and covering yourself from their new angle of attack gives you safety.
Pulling and striking to the previous opening is powerful. If done right, the other person is left with the facial expression that says "I have no idea what just happened here" as they get hit.
Someone said that fencing is like playing chess at 60 miles an hour. Psychology and getting your opponent to do what you want them to do has a big part in the battle.
These are all useful cuts and have many uses. An instructor here is very fond of cutting short edge from a lower guard (Alber or the Italian Boar's Tooth) at an oncoming strike, displacing the attack and then strike diagonally and opposite with the long edge.
We also gained some insight on the flats and how they were used.
We learn to move in ways we are less comfortable with, yet still generate a valid strike. This is a very useful skill to have when the dynamics of a fight becomes unpredictable.
Now that you have a large combination of drill to practice, try to take 30 minutes a day doing the Meyer Square. This becomes both a mental exercise and a physical one.
Hope this helps! :)
P.S. It is useful to note that you can do these drills with other weapons. These are not exclusive to the longsword.