|Invisibles(I):||Beside ordinary units, a given number of Invisible pieces are on the board, their identity and whereabouts being not known. Moves are played so as to determine partially or totally the identity and location of the Is, in order to finally achieve with certainty the stipulated aim. An I may play a quiet move denoted 1.I– (a priori we don’t know which I moved to what square), or may capture a visible unit (1.Ixd5) to show its arrival square. An I remains I until both its identity and whereabouts are determined, in this case it is revealed and becomes an ordinary piece. The notation expresses what we know, and only what we know, all must be deduced, not simply asserted through the notation.|
No. 1572 René J. Millour
original - 26.12.2020
Solution: (click to show/hide)
--Sorry, no animation for this kind of problems (JV)
1... I-- 2.Bd4 Qa2 3.Bc3 Qb1 4.Ixb1 Kg1 #
(Not 1...Qg8 2.Bd4 Qa2 3.Bc3 Qb1 4.Ixb1 Kg1+ → Id2=P, no mate!)
1... Qh8 2.Bb8 I-- 3.Bg3 Qh1 4.Ixh1 Kc1 #
(Not 1...Qc8 2.Bb8 Qh3 3.Bg3 Qh1 4.Ixh1 Kc1+ → If2=P, no mate!)
Both solutions are based on something specific:
I-moves must be played to prove Id2,If2 are NOT Pawns! Twice the wQ is sacrificed to reveal the bK! Specific tries!
The 3 Is are revealed! Mating 0-0 and mating 0-0-0!
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