White: a2-e6;xb3,c4,d5
White could not attack Ge4 right away, because
Black was holding the last move and, more over, could capture
the piece on e7. Through 1.a2-e6;x White recycles
pieces and lines up 3 pieces on the e1-e9 diagonal at the same
time.
Black has 2 options now. He can play 1…b6-g4 and leave
himself a sure way to recycle pieces on the c1-c7 line with his
next move. But that is no solution because White will put a piece
on e8. Black's 2…c7-c4;x will make that spot
c6 becomes vacant and White has a winner with 3.i2-c6;xGe4.
But the second option, 1…a3-f7;x, isn't any better,
because the piece on d6 was Black's defense. So, White
plays 2.e8 and there's nothing Black can do: 2…f8-d8
will be followed by 3.c7-e7 and White captures Ge4
with his next move.
