From: Colin Paul Adams <colin <at> COLINA <dot> DEMON <dot> CO <dot> UK>
Date: 2 feb 1999
Subject: Re: Chu shogi rules update

>>>>> "Rikard" == Rikard Nordgren <e7rikard <at> ETEK <dot> CHALMERS <dot> SE> writes:

    Rikard> What? If the lion could jump to a B square when surrounded
    Rikard> I also think it should be able to return to its original
    Rikard> square and thus pass turn (this makes more sense).

Well, it doesn't. You are arguing by analogy, but the analogy does not
hold. Let us consider the three possibilities:

1) The A squares are all vacant, and so are the B squares. Then it is
permitted to jump to a B square. Likewise it is permitted to move to
an A square, and then return home.

2) The A squares are all occupied by enemy pieces, and so are the B
squares. Then it is permitted to jump direct to a B square, capturing
a piece. Likewise you can move to an A square, capturing a piece, and
return home.

3) The A squares are all occupied by friendly pieces, and so are the B
squares. Then you can neither move to a B square (see - your analogy
does not hold), nor to an A square, so you cannot pass.

In fact, even these three cases aren't proper analogies. The correct
analogy is between a move to an A square followed by a move to ANY
OTHER ADJACENT SQUARE (whether it is a B, or an A or the home
square). The meaning of the pass move is a double move, that happens
to have it's second square coincident with the home square. Therefore
the test is whether a move to an A square is legal or not. If all
the A squares are occupied by enemy pieces, you may make an igui
capture, but not a pass move. And if all the A squares are occupied by
friendly pieces, then you may not move at all (assuming the B squares are
likewise occupied by friendly pieces). Thus the correct analogy is
between the occupation status of the A compared with the B squares.

Note that there are potentially 8 different pass moves, not all of
which may be legal. This would make a difference if Repetition-by-moves
was the rule. But I think everyone agrees that it should be
repetition-by-position (that was the rule used at the Muenster
tournament, and you did not quibble when I circulated the rules
beforehand ('tis a great pity that you could not make it in the end)),
so it makes no difference, and therefore the simple notation Ln !
suffices.
--
Colin Paul Adams
Preston Lancashire