J/A 1 - Yes
this position can be reached legally - see Part B below.
who made the last move through the process of elimination:
note that the White King was the last piece to enter the logjam on the
1st thru 4th ranks, since all the other pieces in that entire sector are
blocked by it.
note that all the pieces must've made their way into the logjam before
the e7xf6 capture, otherwise the White King couldn't have made it to the
Black's h8 Rook needed to escape via h6 at some earlier point, eliminating
h5 as the last move.
the White King was sent to the f4 square at the same time the Black's f8
Bishop was freed by the e7xf6 capture, and since the Bishop still needed
to get to a7, the White King couldn't have made the final move.
The only remaining
possibilities are White's Knight, White's Pawn on a3, or Black's dark-squared
the White King is a sitting duck against any Bishop checks on the h2-b8
diagonal, the White Knight must have blocked checks for two successive
moves as the Bishop moved through c7 and b8 on its way to the a7 square.
6. The only
way the Knight could've blocked for two moves in a row is if White played
the temporizing move a2-a3 as the Bishop moved to b8, so the pawn move
only the Knight and Bishop as candidates, the only way to reach the final
* or Nb5
So, in the diagrammed
position, it must be White's move.
Finding a sequence
of moves to reach the diagrammed position:
minimum number of moves required to reach the diagrammed position is 39,
limited by the longer distance required for Black to move his pieces to
the other side of the board.
At minimum, Black
needs to make the following moves:
7 (Via c7)
one ending up on d2)
one ending up on e3)
7 (From Part A above, we know it must've moved
7 times, as follows, f8-e7-d8-c7-b8-a7-b8-a7)
c7-c6, e7xf6, and h7-h5)
My best was 40
moves (one extra King move for Black). I don't believe 39 is possible,
since the perfect King path isn't available..