2nd TT Pat a Mat C 31.8.2000

Redaction of Slovak journal Pat a Mat announces its 2nd thematical tourney, formal competition for original chess compositions with any stipulation showing pseudo-carousel change (definition see below). Any fairy pieces and/or conditions are allowed as well as twins and more solutions. The tourney will be divided into sections according to the quality and number of entries.

Judge: Juraj Brabec.

Closing date: 31.08.2000.

Problems on diagram with the complete solution should be sent to:
Juraj Lörinc, ul. CSA 333/27, 018 41 Dubnica nad Vahom, SLOVAKIA (or by e-mail to juraj.lorinc@bigfoot.com).

Award will be published in Pat a Mat.

What is it: "pseudo-carousel theme"?

It is very special situation with carousel and pseudo-carousel themes, unusual in the fact that pseudo-"theme" is harder to do than "theme". Carousel theme is well known and many times done, even combined with many other themes of similar or different kinds. Name "carousel" was the Slovak way to express the fact that in this 3-phase theme are defences and mates rotating in the opposite directions. It means that defences and respective mates in phases are as follows:

1st phase:1...a, b 2.A, B
2nd phase: 1...b, c 2.C, A
3rd phase: 1...c, a 2.B, C

Or, when inserted appropriately into table:

  2.A 2.C

Note the diagonal symmetry of table. You see it is one special theme from Z-32-33 family. (3 phases 2 variations each, total 3 defences nad 3 mates.) But there are some other themes in Z-32-33 family and there is one that can be written in the form of cyclic defences or cyclic mates, but not both simultaneously! Just look:
Cyclic defences  Cyclic mates
1st phase:1...a, b 2.A, B
2nd phase: 1...b, c 2.B, C
3rd phase: 1...c, a 2.A, C
   1st phase:1...a, b 2.A, B
2nd phase: 1...a, c 2.C, A
3rd phase: 1...c, b 2.B, C
Or, when inserted appropriately into table:

  2.B 2.C

Note there is no symmetry in this table. And this theme from Z-32-33 family is called pseudo-carousel. Really, it is not the same as carousel change, and as turns out from known compositions showing one of these themes, pseudo-carousel must be done with more intricate motivation. So - is there any reader interested in entering the tourney? I just remark that free places in table may be filled with any moves, or some thematical defences may be refutations or one phase may be set play... they simply don't matter in pseudo-carousel change, but they can make some additional theme. Well, you can see some examples.

Comments to Juraj Lörinc.