|--|--| <-- black attack board
* *
|--|--|--|--| <--- black defense board
* *
1 2 3 4
* *
|--|--|--|--| <--- neutral board
* *
|--|--| <-- white attack board
* *
|--|--|--|--| <--- white defense board
* *
It is of great importance that it be noted that an attack board resting
on an inverted pin can be in the same plane as another board resting on
an upright pin. In the diagram above, the numbers 1 thru 4 represent positions
attack boards might reside at. Notice that while 1 and 3 are locations where
an attack board would be UNDER the defense board, and 2 and 4 are positions
where an attack board would be on top of the neutral board, ALL FOUR positions
are on the SAME level. Thus, for purposes of attack board movement, it takes
THREE turns for a board to travel from position 1 to position 4. In addition,
even though pin position 3 is the nearest INVERTED pin to pin 1, it is NOT
the nearest pin, which is in fact pin 2. As an example of movement, let
us study pin number 2 in the diagram. We will re-draw the diagram below
for clarity:
* *
|--|--|--|--| <--- black defense board
* *
1 |--|--| 3 4
* *
|--|--|--|--| <--- neutral board
* *
2 |--|--| <-- white attack board
* *
|--|--|--|--| <--- white defense board
* *
Notice that Black's attack board is now resting on a pin of the neutral
board. It is important to remember that these diagrams are only
two-dimensional. For every pin indicated, there is a corresponding pin located
on the other side of the boards. In these diagrams, we are looking at the
queens' side of the boards, and thus are dealing with the queens' attack
boards. Refer back to the simple guidelines for moving an attack board.
Assuming the attack board has NO occupants, movement can occur in any of
six directions, as physical pin positions allow. Referring to our example,
the black attack board (resting between the neutral board and the black
defense board) has FOUR options for movement! Three obvious ones are to
pins 1, 2, and 3. The board CANNOT reach pin 4 in this move, however, as
pin 3 must first be traversed. The questions then arises concerning where
the fourth option lies. Remember, for each pin shown in the diagram, there
is another on the kings' side of the board. Four squares away from where
the board is currently resting there lies another pin that we cannot see.
Continuing with the example, let us assume the attack board is moved to
position 3. Renumbering the pins once again, let's refer to the new diagram
below:
2
* *
|--|--|--|--| <--- black defense board
* *
4 1 |--|--| 3 <-- black attack board
* *
|--|--|--|--| <--- neutral board
* *
5 |--|--| <-- white attack board
* *
|--|--|--|--| <--- white defense board
* *
Again, the attack board will have FOUR different moves to chose from. Let's
look at them. The three most obvious ones are 1, 2, and 3. The attack board
cannot move to pin 4, as pin 1 is the nearest in that direction, and must
first be moved to in order to reach pin 4. What of pin 5? Even though pin
5 is the closest pin in its direction (down), it cannot be moved to. The
reason is that a more technical description of attack-board movement remains
the same for travel horizontally, but specifically states that in the vertical
direction an attack board may only 'flip' from the lower pin of a board
to the upper pin, or vice-versa. This movement MUST be associated with a
single primary board. In the case of moving to pin 2, the attack board is
'flipping' from the underside to the topside of the black defense board,
and thus the move is legal. Note that the term 'flip' is being used loosely,
and does not imply that the board is actually turned over. Finally, the
fourth move of the board in this position involves once again the move of
4 squares to the corresponding pin on the kings' side of the board, which
is not shown in the diagram.
A couple more points to be made about attack boards: