The Women’s Protection Units (YPJ) operate in parallel with the People’s Protection Units (YPG). Together they form the backbone of the Kurdish forces. YPJ have become famous during the battle for Kobane, the city at the border with Turkey. The female militias have been involved in all key battles in northern Syria. Women’s Protection Units are a military arm of the Democratic Union Party (PYD), the leading political organization acting in the region. It constitutes the core of the Syrian Democratic Forces (SDF).