No.986 (GF)

Geoff Foster (Australia)


Original Problems, Julia’s Fairies – 2016 (I): January – June

   →Next→List 2016(I)

Please send your original fairy problems to:

No.986 by Geoff Foster – Mates by a single neutral piece. The problem is inspired by No.985. (JV)


KoBul Kings: When a piece (not a pawn) of his own side is captured, a King transforms into a Royal piece of the same type as the captured one. When the King is in the form of any Royal piece and there is a capture of one of the pawns of his own side, he becomes a normal King again. Captures are illegal if they result in self-check by the transformed King.

Phantom Chess: Any unit except a king may move either normally (from its current square) or as though from its Circe rebirth square (game-array squares, of the same colour in the case of pieces, on the file of capture in the case of pawns, and on the promotion square of the file of capture in the case of fairy pieces) if the latter is vacant.

No.986 Geoff Foster

original – 04.01.2016

Solutions: (click to show/hide)

neutral Ke3 Pa2e7

h#2.5          b) nPa2→c2       (0+0+3)
Phantom Chess
KoBul Kings

14 Responses to No.986 (GF)

  1. Diyan Kostadinov says:

    Nice AUW, very clear problem – bravo, Geoff!

  2. Diyan Kostadinov says:

    Actually the last moves in both solutions should be 3…nKxe2(e2=rB) and 3…nKxc1(c1=rS) (instead of 3…nrBxe2 and nrSxc1), because the neutral King is still on its “King” phase before the capture.

  3. Seetharamanseetharaman says:

    hm…. so in Phantom chess, royal pieces have no Phantom power?

    • Joost de HeerJoost says:

      See definition: Any unit except a king may move either normally (from its current square) or as though from its Circe rebirth square.

      A royal piece is ‘a king’.

      • Seetharamanseetharaman says:

        Thanks Joost. Next question:

        Where will a royal knight reappear on being captured in ‘rex-inclusive circe’?

  4. Seetharamanseetharaman says:

    The neutral king is confusing.

    In the following setting can someone tell me why 1.a8B is not mate but Popeye gives 1.Qh2#

    nKh1, nPa7, WQg3. WBb8.

    • Joost de HeerJoost says:

      a8=nB is selfcheck.

      • Seetharamanseetharaman says:

        so.. why .1.Qh2 is not selfcheck in that scheme?
        On that logic why the mating moves in 986 are not selfcheck?

        • Georgy EvseevGeorgy Evseev says:

          > why .1.Qh2 is not selfcheck in that scheme?

          White queen cannot check white king

          > On that logic why the mating moves in 986 are not selfcheck?

          Because “phantom check” squares are different for white and black.

          • Georgy EvseevGeorgy Evseev says:

            Example (phantom chess):

            White want to play npb7-b8=nB

            if neutral king on a3 – illegal selfcheck;
            king on g3 – illegal selfcheck;
            king on e3 – legal check to black;

          • Seetharamanseetharaman says:

            Because “phantom check” squares are different for white and black. >>>>>>
            Thanks. I missed that point !

  5. Nikola Predrag says:

    Diyan, you should define the nature of the NEUTRAL Kobul King.
    When White makes a capture, only BLACK Kobul King transforms.

    So a neutral Kobul King might be compound e.g. as
    neutral “wK+bB”.

    By its nature, a neutral piece is affected differently when White or Black captures it – it has two different rebirth squares.
    And some conditions, like BackToBack, make a different effect on the white/black component of a neutral piece.

    And Kobul King should be affected only when the opponent makes a capture, unless the inventor has explicitly defined otherwise.

    It would be probably interesting to have 2 types of neutral Kobul Kings.

  6. Diyan Kostadinov says:

    Nikola, let we do not make things more complicated than they are. Everything with neutral King being under the KoBul Kings condition is simple – the neutral King is combine white and black so it changes on all piece captures (white/black/neutral) and take the nature of the captured piece. Of course it take back on its King’s phase when a pawn being captured.

    The specific colour differences with the neutral King can be seen for example with a combination with Anti-Circe type conditions in case of captures by the neutral King (neutral Royal Piece). In this case after the transformation the Royal Piece reborn on game array square according that which side did moved – i.e. if the neutral King from a1 capture black Bishop on a2 moved by white side it transform to neutral Royal Bishop and reborn on c8: 1.nKxa2=nrB(nrBc8)

    It is very IMPORTANT that in all captures the King (white, black or neutral) transforms ONLY its nature and NOT its color!

    • Having neutral hybrid on the board, as Nikola suggests, would be confusing. I think the way neutral king is used in the present problem, is simpler and offers better possibilities for understandable problems.

Leave a Reply

Your email address will not be published. Required fields are marked *

You can add images to your comment by clicking here.