Dan and Mike, thanks for commenting.
Mike, Chen Xiang is the former baji guy who is now a disciple of Feng Zhiqiang. CX put in 16 years or so of hard bajiquan training under Ma Yintu from Cangzhou. After that kind of training, one has to wonder how "former" his baji is. Feng himself put in some hard years of training in tongbeiquan and xingyiquan before becoming a disciple of Chen Fake. CX seemed very skilled and smooth in his chansi and application, but that's judging from my comparatively low level.
Feng definitely added in many basic training elements of his own in compiling his (still-evolving) Hunyuan derivation of Chen taijiquan. Just comparing Feng's silk-reeling exercises with Chen Xiaowang's silk-reeling drills, in my experience there is considerable difference. Feng's silk-reeling focuses on loosening the "18 balls" or major joints of the body. CXW's silk-reeling drills, fewer in number, train more of the movement of the whole frame, coordinated with weight shifting. It's easier to translate CXW's silk-reeling drills into the solo form sequences. It's easier to translate Feng's silk-reeling drills into individual applications.
In my time training Chen taijiquan, though, I didn't encounter basic training making systematic use of contradictory tensions like Aunkai does. I'd have to agree that there does seem to be a closer similarity in training method between Aunkai and some southern CMA methods like Hunggar's Iron Wire set (cf. http://youtube.com/watch?v=M02E5hXLmeI
) or the Yijinjing mentioned earlier (cf. http://youtube.com/watch?v=Y72-29g7Tes
) than between Aunkai and Chen taiji training methods.
At a basic level, the "cross" and other lines of tension trained in the handful of Aunkai basic exercises I was introduced to are not found in Chen taiji. Likewise, chansi training is not found in the little bit of Aunkai I've been exposed to. The training and use of the dantien area is different as well, as Dan noted earlier.
Externally, training methods may differ but still make use of the same internal elements--fascia, breathing, etc.--and perhaps wind up supporting some of the same skill sets. Chris Moses reflected on the "Baseline Skillset" thread how, after some months training with Aunkai basic exercises, he could intuitively understand or feel the internal movement that a local Chen taiji teacher was showing his aikijujutsu group.
On the other hand, an external training drill may resemble an exercise in another art but internally be quite different. As Dan noted, that's where the hands-on experience and training time come in. Video clips and detailed descriptions may point the way or mislead . . . it's the limits of the medium.
Thanks for contributing to the thread.