The grain dictates where the split will go, but it is possible to start at either end and split towards the middle.  Then 
you'll be left with a little "bridge" of wood due to the likely deviations of the two splits.  This can be severed with an axe or a heavy machete if the split is narrow and deep.  I have tried this technique with success on a 20inch oak log, 
albiet I have no experience with mulberry.