No.1223 |
Original Retro & PG problems |
Definitions: (click to show/hide)
The -9 & #1 stipulation means: retract 9 moves and than mate in 1 move.
Defensive Retractor: In Defensive Retractors, White and Black retract (take back) a given number of moves (-n moves), in order to reach a position in which a forward stipulation (e.g. #1, s#1) is met. Given a choice, Black will retract those moves that avoid or delay White’s goal. Unless otherwise stated, Black may defend by mating White through a forward move, if such an opportunity exists after one of Black’s retractions.
The different kinds of Defensive Retractors only differ in the way uncaptures are handled, of course only legal uncaptures are allowed:
- In Proca Retractors the retracting side decides, if and what man was uncaptured.
- In Hoeg Retractors the opposite side decides, if and what man was uncaptured.
- In Klan Retractors always White decides, if and what man was uncaptured.
- In Pacific Retractors there are no uncaptures at all.
Anti-Circe (Cheylan): After a capture the capturing piece (Ks included) must immediately be removed to its game array square (necessarily vacant, else the capture is illegal). Captures on the rebirth square are not allowed. Game array squares are determined as in Circe: R, B & S go to the square of the same colour as the capture; Ps stay on the file of capture; fairy pieces go to the promotion square of the file of capture.
The Magic Wandering Unit (MWU) – Convention
1. An MWU moves and acquires the opposite colour on its arrival square. In doing so it preserves the magic power (mp).
2. The magic power is strictly bound to the existence of a unit (except kings). On principle, blank squares do not contain any magic power.
3. Apart from all other (ordinary) units there is only one single MWU ever to be seen on the borad.
4. As to capturing units the following practice has got legal force:
a) An MWU captures and, simultaneously, acquires the opposite colour on the square of capture.
b) An ordinary unit captures an MWU that disappears from the board. At the same time, the capturing unit acquires the mp, thus mutating to an MWU and acquiring the opposite colour on the square of capture.
c) A king captures an MWU. Then the MWU disappears as well as does the mp. The king is, of course, in no way influenced by the mp.
5. As to capturing units under the condition of AntiCirce the following practice has got legal force:
a) An MWU captures – two types are to be classified according to the procedure of changing the colour and the tranfer on to the original square. Type I: the capturing unit acquires the opposite colour on the square of capture and is then transferred to the original square corresponding to the new colour. Type II: The capturing unit is first transferred to its original square and then acquires the new colour. Thus the MWU transports the mp to a new square with each of its captures in the same manner as it does with capture-free moves.
b) An ordinary unit captures an MWU, see (4b), yet as to the new colour and the transfer to an original square, see (5a).
c) A king captures an MWU, see(4c) and wK goes to e1, bK to e8.
6. Whenever there are uncaptures in retro play no additional new MWUs can emerge on the board, see (3).
7. With uncapturing units in retro play under the condition of AntiCirce, the following practice has got legal force:
a) An ordinary unit uncaptures exclusively from he original square of its colour.
b) With type II a whiote MWU can only uncapture from an original square of arrays 7 and 8; a black MWU only from arrays 1 and 2 (see change of colour accoding to (5a). White MWUs on arrays 1 and 2 as well as black MWUs on arrays 7 and 8 can only take back back capture-free moves.
8. Other general power exerted by an MWU works out in the same manner as with ordinary units.
9. In retro problems it must be ensured in any case that the MWU can legally be played back to an original square. If there is evidence of the impossibility of that (virtual) action, the position is illegal!
No.1223 Günther Weeth & |
Solution: (click to show/hide) |
white Ke1 MWb3 Pe7
black Kh2 Qh1 Bg1g2 Pa4c2c4
-9 & #1 Klan Retractor (3+7) |
{no animation for Defensive Retractors (JV)}
1.Kc5:Pc6[Ke1]! bSd4-b3+ 2.wSf5-d4 bSd4-f5+ 3.wSf5-d4 bSe3-f5+ (forced in order to avoid an illegal third identical position (amputated draw pendulum – “adr”) 4.wSf1-e3 bSe3-f1+ 5.wSf1-e3 bPf2-f1=wS+ (forced) 6.Kb5-c5 c7-c6+ 7.wPg5:f6 ep[bPf2] f7-f5 8.Kc6-b5 g4:Qf3[f7]+! (the “wrong” position of Pg5 is legal as it is a MWU. The position can be released by playing bPf7-f5 according to top 9 of the convention for the MWU.) 9.Kd7-c6 & fw. 1.Qg3# Notice: If 7.wPe5:f6 ep[bPf2]?, the position would be illegal as the MWU on e5 would never be able to go back to e7 (original square??, see top 9 of the MWU convention.) Content: By the guidance and the decoy of a magic wandering unit(MWU) in the course of a shortened draw pendulum a white ep- uncapture produces a black pawn obliged to uncapture the white mating unit. (Authors) The retro-problem is featuring "Der Magische Wanderstein" in English "Magic Wandering Unit" (an invention by my friend Günther Weeth). The rules (=convention) were published for the first time in feenschach 213/2015 in German language. Günther has made an English translation for JF readers. (Klaus Wenda) |
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No.1223.1 Günther Weeth & |
Solution: (click to show/hide) |
white Ke1 MWb3
black Kh2 Qh1 Bg1g2 Pa4c2c4
-9 & #1 Klan Retractor (2+7) |
{no animation for Defensive Retractors (JV)
}
solution: 1.Kc5xBc6[Ke1]! bSd4-b3+ 2.wSf5-d4 bSd4-f5+ 3.wSf5-d4 bSe3-f5+ (forced in order to avoid an illegal third identical position = shortened draw pendulum) 4.wSf1-e3, bSe3-f1+ 5.wSe1-f3, bPf2-f1=wS+ (forced) 6.Kb5-c5, c7-c6+ 7.wPe5xf6 e.p.[bPf2]!, f7-f5 8.Kc6-b5 g4xQf3[f7]+ 9.Kd7-c6 – fw.1.Qg3# try: 7.wPg5xf6 e.p.[bPf2]? – leads to illegality due to retroanalysis which shows that there is no way for the wPg5 to finally go back to g7 as a black pawn. The reason for this is the fact that the bPg4 cannot go back to g7 after the 8 th move as a MWU bPg7 cannot uncapture with clearing the g-file. For the same reason concerning now the e-file the defense 8...e4xQf3[f7]+? would be illegal. Granted that this version now proves to be sound, the correction has brought about some improvement with that try in the 7th move and by saving wPe7. (Authors) Accepted by the judge, Dirk Borst, to the competition 2017-2018, as submitted before the Award is made. (JV) |
Such a complex problem using a new fairy piece…..
Well… it’s not all that difficult to understand a piece that changes colour on each move; only the AntiCirce rules (which comes first, colour change or rebirth?) adds some complexity.
Why Black cannot take back f2xg1=B? (Several times in course of solution)
Sorry, my error – Anticirce prevents it, of course.
Obviously, the key is 1.Kc5xPc6[Ke1]! (not 1.Kc5xBc6[Ke1]!). And 5.wSf1-e3 (not 5.wSe1-f3).
Why not 7.wPg5xf6 e.p.[bPf2]! f7-f5 8.Kc6-b5 e4xQf3[f7]+ 9.Kd7-c6 – &.1.Qg3# as an alternative?
Explained in the try description below the solution.
Sorry, misread your message.
And as last move, instead of Kd7-c6, white can also retract Kd7xPc6[Pc7].
9.Kd7xPc6[Pc7] is illegal, Joost. Here is Anticirce, not Circe.