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Constructions
past and present
January 1st, 2008 |
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It was one of the nicest phone calls in a long time. The
Very Strong Chess Player was on the line, asking about my
family, wishing me a Happy New Year's Eve. But soon the
primary reason for the call became apparent. "I've
been looking at your problems, Fred," said the Very
Strong Player. I've solved them all, except one."
Fine, I said, let's go through them. And go through them
we did, one by one, leaving out the problematic December
27 position for the time being. We had a great time doing
this, since we both love puzzles, and we both love the unconventional
and unexpected in chess. And we both have a long history
– just over twenty years actually – of swapping
unusual mind sport puzzles.
In the end we came to December
27th, where my friend at the other end of the line described
the series of moves that led to a helpmate in 22 moves.
"Are you absolutely sure it is 21?" he asked.
"Yes, definitely," I replied, quickly playing
through the solution again to make sure I was not having
one of my periodic mental blackouts. "John sent it
to me, so it is thoroughly checked." That reassured
my partner on the other end of the line.
"But there is no other mate," he said, after
some minutes of humming and hawing. "And this mate
can only be achieved after 22 moves by Black. I thought
about a different mate, but there just isn't any."
Being a very astute problem solver he listened carefully
for my reaction. None came. "Aha, so there is
a different mate?! But where? How? Are you sure?" Silence.
Mutterings at the other end of the line. And then: "Oh,
dear, how could I not see that! Dear, dear, dear."
Except he used a more powerful expletive than the sissy-boy
"dear".
I fondly remember our first Christmas Puzzle, back in 1999,
where I told the story of the problem to end all problems.
This is what it looked like (just one puzzle on Christmas
day, I believe):
Christmas Puzzle
1999
A
game begins with 1.e4 and ends in the fifth move with
knight takes rook mate.

This is the starting position. All
you have to do is enter some legal chess moves, so
that the game ends on move five with the stipulated
knight takes rook mate. |
The puzzle was given to me by (whom else) John Nunn, back
in the 80s. He sealed the answer in an envelope and asked
me to return this unopened, with the solution written on
the back. I passed the problem on to Garry Kasparov and
Anatoly Karpov at the time. The saga of what ensued is described
on the original
page. You can try your hand at it, if you do
not know it already. Please do not write in for solutions
for a few weeks. We will not give it to you without a fight.
Garry was, as you may have guessed, my New Year's Eve caller.
"What are you doing for the New Year's Day puzzle,"
he asked. "I don't know yet," I confessed, which
surprised him somewhat. Weren't these Christmas puzzles
prepared months in advance? No, I usually decide a day or
two before they are published, going through old collections
before I fall asleep. Of course sometimes I have a lot of
help. John Nunn has picked the problems for an entire Christmas
week in the past, and this time I got help from Richard
Saunders, a retired computer programmer from Hampshire,
England, who sent me a collection from which most of the
positions were taken.
Well, after the lovely interlude on the phone I decided
to do another construction problem on the lines of the famous
one shown above (but much easier). I do not give the author
yet – we want our readers to search for the solution,
rather than for the solution on the Internet.

(i) Shortest discovered checkmate
(ii) Shortest perpetual check
(iii) Shortest reflected mate
There are three problems to solve:
- Find the shortest sequence of moves that lead to a checkmate
by discovered check. Naturally both sides are collaborating
to try to achieve this goal.
- Find the shortest sequence of moves after which one
side can force a perpetual. In this case both sides cooperate
until the position is reached; after that one side has
no choice but to accept perpetual. Note that the side
delivering perpetual check prefers it to checkmate, which
he may also deliver.
- Black has agreed to play reflected moves as long as
this is possible, e.g. 1.e4 e5 2.Nf3 Nf6 3.Nxe5 Nxe4 etc.
(so that's where the Petroff comes from!). What
is the shortest mate White can deliver if Black faithfully
reflects his moves? Note that there are three solutions.
We implore you not to send in any solutions until after
January 3rd, when we will have sorted out our mail problem
and sent our spammer to the place were all malicious spoilsports
go. Solutions to all problems will be supplied next week.
In the meantime we wish all our readers
a Very Happy Gregorian Calender Yearly Increment.
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