The Kwan Dao, also known as the Spring Autumn Knife. Shown here the Green Dragon (also known as Reclining Moon) style and the Elephant style.

The Eagle style and the rare Three Edge Two Blade (San Jian Liang Ren Dao) which can be interpreted as two Kwan Dao blades on one end of the staff. Still looking for a weapon that has a kwan dao blade on each end of the handle