The Gaun Sao against the Thai kick pretty much got ruled out when Yip Man's team went to fight against a Thai team and the kicks darn near broke their Gaun arms (might even have broken a couple).

In general, defending long range kicks can be looked at similar to WCK knife vs. pole. (though it will vary slightly if we're talking Thai kick to upper torso vs. Thai kick to legs).

If you have the footwork and timing (and don't get caught by surprise), cut the kick's circle. Close in quickly and attack in a way that destroy's their balance (you can kick the supporting leg, groin, punch the throat/face, sweep, throw, etc.). Staight steps are quicker, angled steps safer. This takes practice, practice, practice...

If you don't have the footwork and timing yet (need more practice), you may have to shield first then move in. Poon Tan Bong (Half Tan Bong, what some call Kwan Sao) is safer on your arms than Gaun Sao, but still takes footwork to set up properly. You can also attack the kick, punching just above the knee-cap, kicking the leg (try to avoid shin-on-shin as Thai boxers often have well conditioned shins), etc.

My classmates wrote an article on kicking in general: http://www.wingchunkuen.com/sumnung/...01_kicks.shtml

Rgds,

RR