Wing Chun Canvas Wall Striking Bag 3 Unit - SHIHAN, New Design With Zipper Protection , Iron Palm. Makiwara Hand Training Sand Wall Bag Wall Striking Bag 3 Section's Wing Chun Kung Fu Sand Wall Bag with Hanging D-Rings (sold Un-Filled) Wing chun Classic Boxing Sand Bag made of Canvas Wall Striking Bag.how to fill your bag.. Rice is generally a good filling to start with. Dried beans like black eyes beans or kidney beans give a slightly harder impact. Sand makes for a dense filling. Very advanced students may wish to use fine gravel or even lead shot. However if you do use gravel or ball bearings or lead shot before you are ready you will not condition your knuckles quickly.