My quest to find the perfect brush for applying winged eyeliner and for smudging into my lower lashline has resulted in a long journey, and a pile of relatively unused brushes. Two brushes have been absolute game changers for me: the Hakuhodo G5512BkSL, and the Hakuhodo K005 which will be the subject of an upcoming review.
The G5512BkSL has a tiny little head with surprisingly short horse hair bristles that are firm, yet not in the least bit scratchy. The edge is beveled so that the you can actually cut a remarkably fine line with tremendous precision and minimal effort. In fact, for the purpose of producing perfectly winged eyes this brush is peerless, in my opinion. When it is a tight and crisp wing that I want, I only ever reach for this brush now. This little workhorse of a brush is also extraordinary for the tightlining (for an excellent tutorial see Everyday Beauty here), which is a fantastic technique that I don't use nearly often enough. If you are accustomed to the shape of the traditional flat tightlining brushes this may take some getting used to. However, I find that the beveled edge of the G5512BkSL allows for greater control and maneuverability than the uniform flat edge of the traditional tightlining brush. For the purpose of clarity the bottom picture shows the head of a traditional tightlining brush.
$15.00 from Hakuhodo.