Hard, Easy,Hard, Easy................

I don't know if it is the same for you, but my experience when learning tai chi is that postures alternate between being hard, then easy, then hard again etc.

I would learn a posture in the form and grapple with the particular requirements and repeat it over and over. After a while that posture seemed much easier to do and I would work on newer postures which were harder.

As I progressed, the postures that had become easier would then suddenly become harder to do. At first this was incredibly frustrating. I couldn't understand why a posture that had been easy to do was suddenly harder.

Of course what happens over time is that your body/mind/energy changes with a deeper understanding and you are creating new neural pathways which affect the way you do the postures of the form. I find that this is an ongoing process so I approach my form each time as if it is the first time - ok, not always :))

This requires you to investigate principles and there is always something to work on. Otherwise there is a risk that your tai chi becomes a hollow performance.