I just watch a match of indian badminton league and the winners wins at 20 -21. I always thought it will be a deuce. Here is the video link.http://www.youtube.com/watch?v=GinjQ1CQFo8, Please educate me.
It's only in IBL. I think there are two differences to the usual system: 1. There is no deuce in first and second set, first player/pair to reach 21 points wins. 2. In rubber set, whoever first to reach 11 points wins. CMIIW
Yip that's right and they have intervals at whomever reaches 7points first and also 14points of one minute, instead of just one interval @ 11points. In the rubber the interval is at 6points.
Here are more details of the rules tweaked for the IBL http://in.news.yahoo.com/playing-rules-tweaked-indian-badminton-league-151113941.html