Your belt cont.
In the West, there were originally two belt colours - White - a novice, and black - one who had finished his "apprenticeship". Then developed the habit of dying the belt to show progress. Initially, the same belt was simply dyed progressively darker colours: for instance:- white, yellow, green, blue, brown, black. Other colours include purple and red, although the grade of these belts varies from style to style.
Nowadays, nobody can be bothered to get the dye out each time you grade. You just buy a new belt from your sensei, so the colour progression is less important, and is no longer influenced by what colour can be modified into what colour - hence the fact that many styles now include striped belts.
In an attempt to provide even smaller achievement increments, which will enthuse new students, many styles, including GKR, offer "half-grades" denoted by tags or stripes. These tags are generally the same colour as the next belt. In GKR, you can attain a single yellow tag on a white belt, a single orange tag on a yellow belt, and one or two black tags on a brown belt. At brown-belt level, it can take two or three years to progress to black, so these tags help to maintain enthusiasm, whilst providing targets for students to aim for.
