You missed my point. In recent years, after a pair from potential Olympic line-up won major titles (WTTC, Asian Games), it is less likely that CNT sends that same pair again to attend the major tournaments (one exception, Zhu Yuling/Chen Meng won 2014 Asian Games). And if a pair has not won major titles, CNT will give them some more chances, like Ding Ning/Liu Shiwen pair and Xu Xin/Fan Zhendong pair (they lost to Ma Long/Zhang Jike in 2014 Asian Games). Free pairings between players are only allowed in national tournaments.
Ma Long/Timo Boll pair is another story. In 2015, the original plan of CNT was Ma Long/Fan Zhendong and Zhang Jike/Xu Xin (not Ma Long/Xu Xin because they won 2011 WTTC; not Ma Long/Zhang Jike because they won 2014 Asian Games; Zhang Jike/Xu Xin did not have major titles at that time and they were more likely to attend 2016 Rio compared to Fan Zhendong and needed to be ready for doubles in team events). Liu Guoliang first planned 3 mixed doubles across countries to draw attention but two pairs (Zhang Jike/Ai Fukuhara and Ma Long/Ariel Hsing) did not work out. Timo Boll requested pairing with Ma Long two months before CNT announced 2015 line-up and Liu Guoliang said it was a compromise because he really wanted to catch people's eyes.
This year, Xu Xin/Fan Zhendong have to prove themselves and Ma Long/Timo Boll are more or less an advocate.
I thought Ma Long is playing with Timo Boll..
Or am I mistaken?
And - question - if Ma Long is playing doubles with Timo Boll, what would chinese coaches like more:
To Ma Long and Timo Boll take the title or the other pure chinese doubles pair?
