Joined: 05 Nov 2005
|Posted: Sat Sep 20, 2014 11:57 pm Post subject: Phases of a composition
|Let us consider a different aspect of a direct two-move chess problem.
This time,instead of named moves, we consider the Phases of the problem.
To locate these phases correctly in relation to moves, we use the following structure:
White's first move <Phase 2>
Black's first move <Phase 3>
white's second (mating) move <Phase 3>
<Phase 1> happens already before the white's first move or rather with white making a null move.
Ie. we consider the initial position with black to play, and thereafter white (possibly) to mate.
These variations in phase 1 are called the Set play and (if they exist) Set mates.
For some problems the set play is a very important phase. Essential for appreciating the problem, really.
Most frequently this happens, when the key does not contain an immediate mating threat, but black finds
himself in zugzwang and any move will allow white to mate. Such a key move is called a waiting key.
More often than not there are several set mates available in such case. Should there be set mates for all
possible black moves, the position is called a Complete Block.
If there is a waiting key that preserves all set mates then good enough.
But often there is no such waiting key and the set mates are broken. Instead there is a key move that changes
the set mates to different ones in the solution. Such problem is called a Mutate and almost always creates a
highly satisfying experience for the solver - provided he/she saw the set play.
<Phase 2> happens in parallel with white's first move and handles exclusively the tries.
Recall that a try is a white first move that fails only on a single black defensive move?
Consequently phase 2 is called Try play or Virtual play and resulting mates (from faulty defences) are try mates.
Note that key move is not part of this phase, but a necessary preliminary to phase 3.
As with other phases of the problem, it is entirely possible that the main emphasis of the composition
rests on squarely on try play. And some composers excel on this. For instance it is said of Sam Loyd,
that you can eventually solve his more devilish puzzles - but only after you have tried all moves!
<Phase 3> consists of variations after the correct key move has been executed.
Therefore this phase is called Post-key play or variation play or simply solution.
Unlike other phases this phase is a necessity in every correct composition.
Certainly many problems assume a comprehensive set of variations. Well-known are
the repertoire ideas of 'knightwheel',initial pawn moves ('pickaninny' and 'albino') as well as
AUW (='Allumwandlung', all possible promotions) expressed as separate variations. Also Task-type
compositions of maximum captures, pins, cross-checks, line interferences etc. rely on rich sets of variations.
In fact you could ask for a task of a problem with maximum number of variations (...and no, I do not know).
<Phase 4> is really an unofficial one, which I call the Afterplay. Here you, as a consumer and solver of problems will express your opinion of the composer's art. Was the key too easy/hard to see? Are all pieces really necessary or are some just doing nothing? Is the position airy or too congested? Was the idea elegantly executed? Was there
in fact any idea? These and many more questions just wait for your input...This phase is already well-represented
on our comments to problems.
So, a two-move problem may have up to three phases with different set of mates. The interphase comparison of
these mate-sets has given a rise to new, modern ideas and themes in a two-mover. These themes are usually named
by the first person introducing them, such as Zagoruyko,Rukhlis, Hannelius, Dombrovsky, Vladimirov etc. -theme.
Common to all of them is that they rely on phases of the problem and are called multi-phase themes.
However, our applet does not support well the presentation of multiple phases and therefore I will skip these themes on our tutorial series this time.
There are only three kinds of chessplayers - those who can count and those who cannot....