No.883 (GG)

No.883 by Gani Ganapathi – Tanagra with Disparate PY condition (can be tested either with Disparate in Popeye, or with Disparate PY in WinChloe). (JV)

Definitions:

Disparate PY: If one side makes a move with a piece of type “x” (black, white, neutral, half-neutral, etc., King included), the other side cannot answer immediately by moving a piece of the same type “x”. (For example: white Qc1, black Ka8,Qa7 – mate in 1 move. After 1.Qc8#, Black is mated because 1…Qb8? is illegal. The mate is possible also with the neutral nQc1 – after 1.nQc8#. Black cannot move the same neutral Queen.) Every Pawn’s promotion is a Pawn’s move, therefore after such promotion (into any possible piece) the other side cannot answer immediately with its Pawn. We can say that after the move of the figure of type “x” any enemy figure of type “x” falls under Half-moving paralysis. This paralysis disappears immediately on the next half-move, if the opponent plays with another piece of type “y”. (“Disparate PY” is implemented as “Disparate” till the latest version of Popeye, PY 4.73. In WinChloe this version of Disparate is available starting version 3.32.)