
He also wondered what use kokutsu-dachi would have in sparring. He also questioned the traditional statement that stances are transitional positions, not something you hold through a fight. Here was my response, but I'm not sure if I'm barking up the right tree. Would some more experienced karateka let me know if I'm thinking about this in the right way, or if I'm missing the point?
(My tentative analysis follows):
I disagree that you never see kokutsu-dachi or other kata stances in kumite. From the "neutral sparring stance" pictured above, if you throw a kizami zuki, your body will momentarily be in a position not unlike back stance (though not nearly as pretty as in kata):
http://www.youtube.com/watch?v=UjDgg_npiQM
Now from that beginning neutral position, if you throw a yaku tsuki, you end up in front stance at the moment of impact:
http://www.youtube.com/watch?v=KC_xt9RLKEg
You say boxers hold the same stance throughout a fight. I'm not so sure. A boxer wouldn't hold a stance with one of his shoulders all the way forward as if he was mid-punch, would he? The shoulders are in a neutral position and rotate in various manners depending on how he's punching.
A karateka's hips are like a boxer's shoulders. Their rotation is how power is generated. Different stances are various positions you're in at the moment of impact. They're complete extension of hip rotation in one manner or another. They're not meant to be held between techniques, because then you couldn't rotate your hips and body in whatever manner you need to do to power the next technique if you're not starting from a neutral position.
