From: Pieter Stouten EMBL BITNET>
Date: 20 aug 1990
Subject: Hisshi problem -- Shogi CAN be beautiful !
On 13-Aug-1990, Klaus Blumberg DBSTU1 bitnet> gave the
following "Hisshi" (=despair) problem, which was published earlier in
"How to play Shogi" by John Fairbairn. Hisshi problems are like "Tsume"
problems in the sense that the solution leads to a forced mate.
Contrasting with Tsume, however, the solutions to a hisshi problem
always contains at least one NON-CHECKING move.
5 4 3 2 1
-------------------------+ Black in hand: Silver.
|+bR | | | wN | wL | a
-------------------------+ White in hand: everything else
| | wG | wK | | | b
-------------------------+
| wP | wP | wP | wP | wP | c
-------------------------+
| | | | | | d
-------------------------+
| | | bS | | | e
-------------------------+
According to Fairbairn, the solution is 1.S'3a and against every
conceivable defence 2.Sx4b+ and 3.G'3a, followed by 3. ... K2b 4.Gx2a
K1b 5.Gx1a K2b 6.+R2a leads to mate. As Klaus Blumberg pointed out,
this solution is incorrect when the piece which is dropped in defence
after 1.S'3a covers 3a after recapturing on 4b. To make clear what I
mean: after 1.S'3a S'4a 2.Sx4b+ Sx4b, the proposed continuation 3.G'3a
fails to Sx3a. The same is true for dropping a bishop in defence with
e.g. 1.B'6d. But even after dropping neither a Silver nor a Bishop in
defence, the solution is not so straightforward as the one published
led us to believe. Because this is really an elegant problem and
because Hisshi problems are surely worth looking into (although they are
a great deal more difficult than Tsume problems), I give here the full
solution that I found and of which I am pretty sure it is correct.
1.S'3a and now there are two main lines, not defending (A) or
defending (B) 3a after recapture on 4b:
A) 1. ... L'4a (G'4a or R'4a ar equally possible, but a lance is least
useful to black, when he gets it in hand) 2.Sx4b+, and now there are
two possible replies: A1) 2. ... Lx4b and A2) 2. ... K2b
A1) 2. ... Lx4b 3.G'3a K2b 4.Gx2a K1b 5.Gx1a K2b 6.+R2a. This is
the solution Fairbairn gives.
A2) 2. ... K2b 3.+Rx4a
A2a) 3. ... K1b 4.G'2b Kx2b 5.+R3b mate.
A2b) 3. ... P1d (trying to create an escape route) 4.S2d
(blocking the escape route) and now 4. ... K'1b has the
same outcome as variant A2a, so white must take on 2d:
4. ... Px2d 5.+R3b K1c 6.G'2c mate.
This shows the beauty of the problem. Every piece has its role and
even the Silver on 3e becomes active. The Gold captured on 4b can be
used for the "shuffle" on the back rank or for a mating drop on 2c.
B) 1. ... S'4a (or B'6d) 2.Sx2b+ and now 2. ... K2b 3.Rx4a leads to
the same result as variation A2. Therefore: 2. ... Sx4b (or Bx4b)
3.G'2b Kx2b 4.+Rx4b. White can now interpose any piece he likes on
3b, but after 5.S'3a (or B'3a) K1b 6.+R3b it is mate. As in Tsume
problems, the position after 6.+Rx3b is regarded as final. White can
still interpose on 2b, but this drop merely sacrifices an undefended
piece and does not change the essence of the final mate. I agree that
this rule is not as clear-cut as it should be, but this is how it is.
In practice it is easy to distinguish a "useful" defending move from a
useless one, however.
So, as Klaus said, the solution is incomplete, but putting up a better
defence (with S'4a or B'6d) eventually gives black a more useful piece
for his mating attempts. Shogi CAN be beautiful.
Pieter Stouten embl bitnet>