Its seed coat is hard and thick, you have to grind off the tip (germination point) a bit before soaking in water, this will ease and speed up the germination.
2 c! I$ Y0 Z7 M' Q8 ?- X+ x+ j
If you mean those from chinese groceries store, it may not be possible to germinate, I guess they are dried and the protective seed coat was peeled off. They are lifeless food stuff.