The server is the player who starts the rally, and the service court depends on the score. In simple terms, even scores mean serve from the right side, and odd scores mean serve from the left side. This is one of the easiest badminton scoring rules to remember once you see it a few times. The idea is not random. It gives the game a clear pattern and tells you exactly where to stand before each serve. After every rally, the service changes only if the server loses the point. If the server wins the rally, the same player keeps serving, but they switch service courts if their score changes from even to odd or odd to even.
In singles, the serving player stands in the right service court at 0, 2, 4, 6, and so on. At 1, 3, 5, 7, and so on, they serve from the left service court. In doubles, the same even and odd idea still applies, but the rotation between partners adds another layer. That is why beginners often feel more comfortable starting with singles scoring first. The pattern is easier to see, and once that makes sense, doubles becomes less intimidating. Clear scoring habits are part of good match control, just like footwork and shot selection.