They've had several Asia sales this year; the first one was really lame, the last one ok-ish at least for some places, but there were very few hotels where the discount was 50% (to be fair, during the last Japan sale, there were some hotels where the Japan sale didn't offer a 50% discount, because had raised their rates). I would expect another Asia sale in a matter of weeks (and you might also want to check the F&F rates).

I used a BOGO at the Strings on one of these rates (but I think the Strings was one of the hotels that had jacked up their rates before the sale). IC's policies on which rates apply to the BOGO is a total mess. Generally, I expect that any rate booked on the IHG website qualifies, and I am prepared to argue this point with the manager, or, if they refuse, Ambassador services.