Anyone who has ever done Do-In or yoga recognizes this: one stretch is easy for you, while you feel a lot of resistance in the other stretch. Sometimes there is even a huge difference between the two sides. We call one place full, or Jitsu. The other spot is empty, aka Kyo.
That the energy fluctuates and is sometimes full, then empty again, is a normal process. It only becomes annoying when obstruction arises. To explain this, let me give some examples. Just think of the lunar cycle: full moon, waning moon, new moon, waxing moon. This is a very natural process. In our body we also see this in the respiratory cycle: with inhalation, the lungs are full, and with exhalation they are empty. There's nothing wrong with this. As I wrote, it only becomes annoying when a blockage arises: if you wait long enough after your exhalation to inhale, you will feel how annoying it is to experience emptiness.
Through stretches, self-massages and visualizations we can redistribute the energy. Ideally, you start with the easiest (the kyo/empty) side or exercise. You can stretch or massage the easiest side. This removes any blockages so that this side can receive energy. Then you work with the most difficult (Jitsu/full) side. You can massage this a bit more firmly and stretch it deeper if you like. The blockages disappear, after which the energy can be equally distributed again. Because you handled the kyo side first, the released energy has a place to go.
In the above exercise, you start with the soles of your feet together, knees lower to the sides. First, determine which leg feels most relaxed in this position. Here you experience kyo. Massage the inside of the thigh on the kyo side with your elbow: give pressure during exhalation, and move during an inhalation. Return to the starting position after a few minutes. Notice any difference. Then switch sides and deal with the Jitsu side. After a few minutes, return to the starting position and feel.
You can proceed in the same way with all stretches.
This is a nice accessible way for self-treatment. Do you want to go deeper? TCM therapists, or Do-In teachers I have trained at Do-In Academy, have learned to investigate Kyo and Jitsu even more precisely so that they can work with you in a very focused way towards balance. If you want to learn this yourself, I would like to welcome you to Do-In Academy.