Chess Problems: Pinning Themes
By David Friedgood
The first problem shows two ways in which Black may allow pieces to become
pinned – this motif is called the self-pin. The problem is complex, yet
clear: in the set play (where the diagram position is considered under the condition
that it is Black to move), the half-pin is demonstrated. After the key, the
nature of the position is changed considerably and the same former half-pin
defences are turned into a special variety called Nietvelt defences.
[Event "4th Prize, Moscow - Rostov"] [Site "?"] [Date "1930.??.??"] [Round "?"]
[White "Mikhail Barulin"] [Black "Mate in 2"] [Result "*"] [Annotator "Friedgood,David"]
[SetUp "1"] [FEN "8/1p5p/1P5B/2K1p3/QP2N3/Pr1P4/1Rb3N1/n2k1B1n w - - 0 1"] [PlyCount
"3"] [EventDate "1930.??.??"] 1. -- {This is what is known as a block position:
if it were Black to move, then every move would permit White to mate. All that
is needed is for White to play a pure waiting move that does not disturb the
set mates, but there isn't one! For example, all moves by the white king can
be met by a ruinous check and moving the h6 bishop releases the h7 pawn. Going
back to the diagram position, if we look at the set play (the mates that would
occur if Black had the move),} (1. Qd7 $1 {is the answer to the problem: now
Black has a threat to deal with.} -- (1... Rxd3 {This is a self-pin of a special
kind, known as a Nietvelt defence. The black rook, in capturing the d3 pawn
allows itself to be pinned by the queen, as the latter would have to unpin it
to execute the threat 2.Qg4, and this would in turn permit the rook to interpose
on f3. But of course White finds a way of taking advantage of the pin to give
mate by} 2. Nc3#) ({Similarly,} 1... Bxd3 {is another Nietvelt defence, this
time the self-pin of the bishop (together with the line-opening of the b2 rook
to control e2) allows White to mate with} 2. Be2#) {Threat:} 2. Qg4#) 1... Rxd3
{ is another form of self-pin: the rook moves off the queen's diagonal to d1,
leaving the bishop pinned and no longer controlling b1.} ({Similarly, when the
bishop moves off the queen's line by} 1... Bxd3 {the rook becomes pinned and
mate can follow by} 2. Nc3# {This construct, where a piece moves off a line
revealing a pin on a piece of the same colour, is called a half-pin.}) 2. Rb1#
{The pioneering composer has cleverly combined two of the main kinds of self-pin
by Black into a single problem.} *
The second problem neatly shows one of the most popular traditional two-mover
themes, the Schiffman Defence.
[Event "British Chess Federation"] [Site "?"] [Date "1932.??.??"] [Round "?"]
[White "A P Gulayev (Grin)"] [Black "Mate in 2"] [Result "*"] [Annotator "Friedgood,David"]
[SetUp "1"] [FEN "4B2Q/2K5/6PN/R3p2k/2N4p/8/6r1/1b6 w - - 0 1"] [PlyCount "3"]
[EventDate "1932.??.??"] {In this position, the solver would note that the black
king has a flight square on g5. In spite of the fact that it opens the white
king to a check, the key is} 1. Nxe5 $1 {This move guards both g4 and g6 in
order to threaten mate by (see below)} -- {Threat:} ({Black's thematic defences
are very similar to the Nietvelt. Captures on g6 cause black pieces to become
pinned by the e8 bishop such that, if White were to execute the threat, they
would be unpinned and would be able to interpose to cut off the check. Thus}
1... Rxg6 {prevents the threat from being mate, but because of the self-pin,
the rook can no longer move to g5 and now} 2. Nd3# $1 {cuts off the bishop from
f5 to effect mate.}) ({Similarly,} 1... Bxg6 {prepares to interpose on h7, but
now it has lost the ability to move to f5, so White this time cuts off the rook
in forcing mate by} 2. Neg4# {These two black defences are known as Schiffman
defences. They are very similar to Nietvelt defences, in that they allow a black
unit to become pinned, in the expectation that execution of the threat will
unpin them and enable them to prevent mate. But the feature differentiating
the Schiffman from the Nietvelt is that the white pinning piece (in this case
the e8 bishop) does not execute the threat, which is instead executed by another
piece (in this case the h6 knight). Over many decades of Schiffman two-movers
this feature has proved to offer a greater variety of possibilities to the composer})
({The non-thematic defences are:} 1... Rc2+ {The drawbacks of this check are
that the rook can no longer interpose on g5 and at the same time it interferes
with the bishop:} 2. Nc4# { (a switchback)}) (1... Kg5 2. Nd3#) 2. Nhf7# {A
pleasingly lightweight problem, showing Schiffman defences with crystal clarity.}
*
The last two diagrams are for the reader to solve. In each case, you have
to find the unique key move for White, after which Black is unable to avoid
mate on the second move regardless of what the defender plays. Explore the
variations created by the Black defences and see if you can distinguish the
themes discussed in the first two problems. Note that the first of these problems
for solving has a bonus in the set play – the composer has achieved
a particularly clever combination of themes.
Mate in two moves
Mate in two moves
Solutions will appear in approximately one week.
Any queries or constructive comments can be addressed to the author at david.friedgood@gmail.com.
Copyright in this article David Friedgood 2012/ChessBase
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