Well.. if i understand you correctly.. and soldier is a pawn..
white pawn - c7
black rook can then d6,d7,d8
d6+ then white king to c5
d7 then white pawn to c8 to queen
d8 white pawn x d8 for win in 20 moves..
if the soldier piece is a bishop, knight, or rook this is very different.. rook can only give stalemate as i believe if the case also with knight, and bishop.
*note* i only showed up till the queen.. after that white secures win.