Flow is an important Wing Chun principle. It is through flow - the linking of techniques in a smooth sequence - that the art comes fully to life. Sometimes it is possible to stop and defeat an attacker with one strike. We might defeat an attacker with a swift pre-emptive strike, kuen siu kuen or basic lan da, tan da, gan da, pak da etc.
Often defeating the opponent requires a sequence of strikes. We might chung choi, fuk sau and ko jeung. We might darp, fuk sau and chung choi. We might pak, pak da. We might do lan sau chung choi, ko jeung and huen ma or employ kim yeung ma to throw or take the opponent down. There are numerous examples. Any and every sequence involves flow.
Flow integrates deflection, striking, stepping, trapping, and kum na. Flow entails the alternation of yum and yeung, essential for an understanding of Wing Chun if not of any gung fu. At times flow is only of short duration. At others it is a few more moves. Without it we see a very static, robotic Wing Chun.
Trainees have to approach flow in a systematic learning process beginning with the basic elements and moves and gradually learning san sau routines which flow smoothly from technique to technique. Mostly flow will entail deflecting and delivering several counters but occasionally, if your opponent is a skilled fighter you may have to deflect two attacks before you can hit them. In these cases flow involves transitions from your initial attack to a deflection and then your second attack. The sup yee sik can be woven together according to circumstantial demands in a flow. Flow is a principle which exists in an integrated fashion with all the other elements of Wing Chun and the other principles. Often overlooked or left unarticulated, it is nonetheless essential for mastery of Wing Chun.