No.218 (KP&DB)

Kostas Prentos & Diane Barnard – welcome to Diane, Kostas’s wife!


Original Problems, Julia’s Fairies – 2013 (I): January – April

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No.218 – “Half-check Chess” by Kostas Prentos & his wife Diane Barnard –  family-made problem with unusual condition! Have to add that Half-check Chess is not programmed, so the problem is not computer tested. (JV)


In half-check chess, the effect of a check is delayed for a while, i.e. the checking piece loses the power to capture the King. This is called half-check, it is denoted as (+) and it becomes fully effective only after the next move, if the checking piece and the king remain in half-check position during the play. This is a full-check and it is denoted as + (it is check in the ordinary sense). Checkmate is delivered by full-check.

No.218 Kostas Prentos & Diane Barnard
h#2            2 solutions        (3+7)   C-
Half-check Chess
Solutions: (click to show/hide)

3 Responses to No.218 (KP&DB)

  1. SeetharamanSeetharaman says:

    Sorry. It is a little confusing. If black king is allowed to move
    3.Ke6 (in the first solution) when a WQ is on e8, why is that move not permissible when a WR is on e8 ?

    • Kostas Prentos says:

      According to the definition of this fairy condition, it is illegal to move into check (expose the King-like in regular chess), but the King can remain into half check for one move.
      So, to answer your question, the promotion to Queen on e8 is half check, which means that the move 3.Ke6 is allowed. In the case of Rook promotion, the Re8 does not give half check, so the move 3.Ke6 (or 3.Kxd8) is not allowed. The mate comes from the Queen on d8, whose half check on the first move, becomes full check on the second.
      I hope it is clear now. I did a quick check to find the Sake award in the 2010 WCCC bulletin, but it seems that it is not available online anymore.

      • SeetharamanSeetharaman says:

        Thanks. I see the point now. It is ok, to move from a diagonal check (ie. half-check) to lateral half-check of the same piece (the black queen), but not into a new check ! Very interesting condition and nice demonstration of the possibilities.

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