the first belt in karate is white
A white belt
Every school that I know of starts with a white belt.
the next kaigan karate belt after white is orange
White is always first. The one consistent part of the belt sequence between all of the schools and martial arts is they start with white and end with black.
The traditional starting point is the white belt. Every style I know starts with white. When you buy a new gi, it typically comes with a white belt.