This hat starts with a flat tubular cast on which is joined in the round for the color work section. The color work is done with sport weight yarn and even though the finished product looks very complex, each individual row is easy to tackle. After the chart is completed, the yarn switches from sport weight to worsted weight so that the plain stockinette section is faster to knit. A row of decreases takes care of the gauge difference.
If knitting in other colors, make sure that the main color sport weight (in this case black) matches the worsted weight (again, black) almost exactly for a seamless transition between the two.