On yet another occasion we saw the Expedite Rule introduced to a match at the 2012 WTTC. Some of you may not be aware of the bizarre ruling so I thought I would explain it.
The expedite rule comes into play if a set has lasted over 10 minutes in length. This usually occurs with extremely patient players or defensive players, as in Kim Kyung Ah and Wang Yuegu's case in the final deciding match of Singapore vs. Korea. The rule can only be introduced if less than 18 points of the set have been played, in this case it was introduced at 9-8 (17 points).
Another umpire enters the playing area and the game changes. Each player alternates service (1 serve each). The server must win the point within 13 strokes, otherwise the receiver wins the point. The rule stays in place until the end of the match.
In my personal opinion, the expedite rule should be abolished. It puts far too much pressure on players in crucial moments of big matches, and often interrupts the rhythm of the match. Defensive players have often had more exposure to the rule, so this can give them an unfair advantage, though Wang Yuegu did well to avoid defeat in this scenario. Hope that helps explain the weird rule!