It's not that they are difficult. In fact, they are quite straightforward. They just require absolute concentration. This is not a "knit and watch a movie" kind of project. This is "sit up and pay attention" with the pattern being consulted every single stitch and every single row.
The chart is terrific, but the instructions are a little skimpy. If you are a proficient knitter you will easily figure out where and how to put in the increases and decreases, and what "reverse pattern for second mitten" means. And then there is the thumb!
The pattern is a lovely traditional Norwegian snowflake pattern. I love it.
Now that I'm nearly done and I know how much yarn they take, I've got a plan to make a few more pairs in my hand spun. Should be lovely.
BTW the pattern is Norwegian Selbu Mittens by Henrietta Hope. It's a free download on Ravelry or here.