Yin and Yang (or his and hers!?) are two patterns in one. One is knitted straight with a slit for the thumb (brown version in Sirdar Chunky with Wool) - this is the easier version and is for those who are not confident enough to use double pointed needles. The other is knitted in the round with a true thumb (cream version in Rowan Alpaca Cotton). The cable pattern is a mirror image between left and right mitts, so the pattern instructions are written for each mitt separately.
Instructions are given so that you can increase the length of them if you wish.