Today I tried playing the 'old' format of doubles.
This is style is the side by side format, where each player selfishly guard their own side.
Basically, no one smashes but played clears and drops only.
The advantage of this 'old' tactic are clears uses more energy than a smash and the front back movement served to tire the opponent and causing errors.
This tactic is acceptable in the old 15 point system where stamina is more important than speed. If the opponent cannot clear back to back, then he is vulnerable to a drop in front court or some hold and flick. Unfortunately, this tactic may cause the opponent to target only one player and the other player is not 'involved'.
I find it a bit boring as it's like two single players playing on one side of the court.
But this tactic forces you to 'control' the shuttle and helps improved your placement.
Although not exactly what I am planing to illustrate, LiYong Bo's defensive style here was the side by side, but the Danes adopted a front back position anyway.
Here is a 15 point system mens doubles at the highest leve lin 1986.