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Phases of Play
Peter's Problem World with FIDE Master of Chess
Composition
Peter Wong
In this column Peter provides help with words or phrases that have special
meaning in the field of chess composition. These words and terms
appear in the form of a pop-up box
containing a short explanation and possibly a link to an explanatory page
or example elsewhere. Click on the words "pop-up box" in the last
sentence to try it out!
|
The full solution of a
directmate problem often consists of
more than the
key-move that solves it and the
ensuing variations. In addition to the
actual play that follows the key,
there may be other
phases of play, such as set play and
try play, that are of
thematic interest. Set and try
play are distinct groups of potential variations that tend to be considered
naturally when solving a problem. Furthermore, a problem may
incorporate several phases of actual play, either by using the device of
twinning to create multiple settings, or simply by calling for more than one
solution.
Set play is what would occur if
the side that normally moves first could miss a turn. So in a
directmate, this phase of play refers to any variations that are already
prepared in the diagram, before White makes the key. |
|
|
7. Henry D’O
Bernard
Chess Amateur
1918
Hon. Mention
  
 
  
Mate in 2 |
In Problem 7, if Black were to
begin, we find that every possible move has been provided with a mating
reply. The set play is therefore: 1…f4 2.Qe4, 1…Rc5 2.Nxb4, and
1…R-else 2.Qb5. A non-disruptive move by White that preserves
these set mates would solve the problem, but none is available. Instead, the key 1.Nb8! (waiting),
by giving the black king a
flight square on c5 and putting an
extra guard on c6, surprisingly changes some of White’s mating responses:
1…f4 2.Qh5, and 1…Rc5 2.Qe6. The other rook variation is
unchanged, 1…R-else 2.Qb5, and the king’s flight leads to an added
mate, 1…Kc5 2.Qc6. Set play is notable thematically when it differs
from the actual play, as here, giving rise to
changed play. |
A first move by White that nearly solves a directmate,
but is defeated by only one black defence, is called a
try. In notation, a try is signified
by ‘?’, while its defeating black move – known as the
refutation – is indicated by ‘!’.
| In Diagram
8, if the white king moves to guard e4, 2.Rd6 will be
threatened. The king has three approaches to e4, and two of them are
thematic tries. 1.Kd3? makes the error of closing the d-file, and it is
refuted by 1…Rxc5!, a
self-blocking defence that would have
permitted 2.Rd1, if not for the white king’s placement. Likewise 1.Kf3?
closes a vital line, this time the long diagonal, so that 1…dxe6! refutes,
as White cannot take advantage of this self-block with 2.Bg2.
The last way
to attack e4 is the key: 1.Ke3! The black moves that previously
worked as refutations are now answered by the unhindered white mates,
1…Rxc5 2.Rd1 and 1…dxe6 2.Bg2. One
by-play variation is
1…Rc6 2.Re5. |
8. David Shire
The Problemist
1990
 
 
Mate in 2 |
In the previous example, the closely related tries (and
their refutations) are sufficiently interesting by themselves to represent a
large part of the problem’s content. Another type of try creates even more
content, by introducing variations that are different from the actual play.
Such variations make up a phase that is called
try play or
virtual play.
|
9. Norman
Macleod
Correspondence Chess
1962
5th Hon. Mention
 
Mate in 2 |
Problem 9 neatly
illustrates this, along with the
focal theme. The first try
is 1.Nd4? (waiting), after which the black bishop is “focusing” on two
possible mating squares of the d4-knight, b3 and c6. Upon moving, the
bishop is forced to “lose the focus” and un-guard one of the two squares,
e.g. 1…Be4 2.Ndb3, and 1…Be6 2.Nc6. Black cleverly defeats this try with
1…Bb7!, cutting off the rook on b8, so that 2.Ndb3 doesn’t mate. Another
try, 1.Nd6? (waiting), leads to a different pair of knight mates following
the bishop moves, 1…Be4 2.Nc4, and 1…Be6 2.Ndb7. But Black employs the same
tactic as before to refute: 1…Bb3! shuts off the other rook, so that 2.Ndb7
would only check.
Finally, the key 1.Nc3! (waiting) controls a4 and
frees the other knight to give a third pair of mates, 1…Be4 2.Nb3,
and 1…Be6 2.Nb7 (also 1…Bb3 2.Nxb3, and 1…Bb7 2.Nxb7).
Three pairs of changed mates are thus shown in this
two-mover. |
A
twin refers to multiple settings of a
problem, which differ from one another slightly in their positions, but each
requiring its own solution. The settings are produced by making small
adjustments to the initial diagram.
| Problem 10 demonstrates such a
twin with two parts. The diagram position is regarded as part (a), which
solves normally. The
stipulation then specifies that part (b) be
formed by shifting the black king to h5, and this position is to be solved
anew. Besides shifting a piece to another square, other methods of twinning
are possible, such as adding or removing a piece, and replacing one piece
with another. Part (a) of this problem starts with 1.Be3!, which
threatens 2.Nh4. Black has only two defences, both self-blocks that provoke
queen mates, 1…Rxg6 2.Qf3, and 1…Nxg6 2.Qh3.
Part (b) has the
key 1.Bxf6!, threatening 2.Nf4. The same defences by Black are
playable, but they lead to a special type of changed play called
reciprocal change. In this scheme, two White mating moves that work
against two defences respectively in one phase are effective again in
another phase, but these mates have to be swapped in dealing with the two
defences, so here 1…Rxg6 2.Qh3, and 1…Nxg6 2.Qf3. |
10. Josef
Retter
Hashavit Memorial Tourney
1982
3rd Prize
Mate in 2
(b) Kf5 to h5 |
Directmates that involve multiple solutions, i.e. those
requiring more than one key to be found, are relatively uncommon but quite
legitimate. Additional solutions are of course distinguished from
cooks
in that the former are intentional, and their presence in a problem is
always indicated in the stipulation.
Return to Peter's Problem World
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