10 years ago I started studying Wing Chun with one Sifu. Some time after that I moved to another country and changed lineage. Nowadays I train in private with another Sifu (same lineage as my previous).
My question: who is my Sifu? First one or the last one?
I'd say both. Technically speaking, sifu doesn't even mean teacher (that would be laoshi), but skillful master. If the first one laid the groundworks for you, the fundaments on which the second one builds, both have formed you, so both are your teachers.
It's no different from training, say, wing chun in one club and tai chi in another. You won't say the wing chun is your teacher, but the tai chi one isn't. It's unavoidable that wing chun and tai chi won't mix together in how you use it, if you train both, so even if you stop either one, the teachings from that one will still be in you.
The same goes for doing wing chun from two teachers, as long as they formed you up to the point you're carrying it in your other training.
Does it have to be only one? I have had multiple ones and each of them taught me a part of their reality. They both have been part of your life and your training.
Plus, I believe this lineage is different in modern times since practicing Martial Arts is not only limited to a selected few.
There are at least two ways people think about lineage:
Case studies (these terms are my own and are for illustrative purposes rather than a complete classification):
successor Both senses of lineage apply. Successor is too strong a term for the general case where both senses apply, but I can't think of an existing term for the general case.
dilettante Student thinks they are in teacher's lineage, but the teacher does not consider the student sufficiently advanced to be in their lineage. Other less derogatory terms, including simply student, also apply.
renouncer Student graduated from teacher, but student thinks they have learned much more important skills later from others. Teacher claims importance of their teachings.
mixed-martial-artist In the original sense of this term, this meant a student studied multiple martial arts systems and became proficient in more than one. This places the student in multiple teacher's lineages. Nowadays, it may actually refer to a particular martial art system learned from one teacher.
As you can see, lineage is not a simple concept.
Based on your question, I think you have had three teachers from two distinct lineages. Based on the information you have provided, you could be in the lineage of any subset of those three teachers, depending on what definition of lineage you are using.
