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  (1) Posted by Hauke Reddmann [Tuesday, Aug 27, 2024 09:59]  Cool construction problem from CSE Lucenaposition stipulated:
Some Chess960 starting position, h# where the mating side only moves the K.
"Impossibru!" means you didn't pay close attention :), but you are
problemists and surely see the trick immediately. I tried myself and
came to a singledigit number. (Which surely isn't the possible record.)   (2) Posted by Hauke Reddmann [Wednesday, Aug 28, 2024 10:06]  Update: A post confirmed with Jacobi that my solution attempt with 6 moves is optimal.
https://chess.stackexchange.com/questions/46091/checkmatewithkingmovesonly   (3) Posted by Hauke Reddmann [Thursday, Aug 29, 2024 09:56]  Son of update: With pawns only.
https://chess.stackexchange.com/questions/46096/checkmatewithpawnmovesonly
With knights only is left to the reader :)   (4) Posted by Per Olin [Sunday, Sep 15, 2024 12:40]  An interesting question in post nr 1 related to the Chess960 castling rule. Turning the question to have a long solution, it seems to be possible to have a unique initial position.
(= 15+10 )
Minimum number of moves and from which Chess960 initial position in a game, where Black has made moves only with his king?
From the diagram, stipulation and posts above the initial positions of four pieces are obvious: bKf8, bRg8, bQh8, wBb1. When the play starts with 1.c3, then is closed the direct move by wRa3 along the third rank to d3. Both white rooks make the moves Ra1a3b3b4(5,6) etc. The wBa1 can not start on a1 or c1 as when making the pawn move b2b3 to enable Rg1a1, then the way for the rook via b3 is closed. Therefore, the wBa1 starts on e1 and with the initial move 1.c3 there are needed 5 moves to reach a1. For the second white rook the optimal initial position to minimize the number of moves is a1, which leaves c1 and d1 for the knights. The black pieces on a8e8 are captured by a white knight. White move count from RBSSBKRQ: pawns 7; knights 22 (the knight move sequences can be tested by Jakobi sera=>b stipulation); bishops 6; rooks 10; queen 2; king 4; total 51.
Solution: 51 moves from the Chess960 initial position RBSSBKRQ.
             
An alternative way of expressing the stipulation could be: 'Position after 51 moves in a game, where Black has made moves only with his king. Chess960 initial position?' In this case would be revealed that there is something tricky with the solution. This is that the forced first move 1.c3 prolongs the way for both wRd3 and wBa1; better to leave this for the solver to find out or not to find out.   No more posts 
MatPlus.Net Forum General Cool construction problem from CSE 


