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Subject: Re: King Night Bishop - 50 Moves

Author: Steve Coladonato

Date: 15:10:39 04/22/99

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On April 22, 1999 at 15:46:27, Jeremiah Penery wrote:

>On April 22, 1999 at 14:45:19, Steve Coladonato wrote:
>
>>
>>On April 22, 1999 at 14:26:24, Jeremiah Penery wrote:
>>
>>>On April 22, 1999 at 13:05:04, Steve Coladonato wrote:
>>>
>>>>At one time, there was a rule in chess that in the case of a known forced mate a
>>>>player was allowed the standard 50 move rule or twice the number of moves with
>>>>best play to execute the mate.  The KNB vs K ending is a 34 move ending  with
>>>>best play.  Therefore a player was allowed 68 moves to effect the mate.  Does
>>>>anyone know if this rule is still in effect?
>>>
>>>Can you post a position for this?  The longest ending of this type that I've
>>>seen is something right around 50 moves. (The losing king is in the wrong
>>>corner)
>>
>>The 34 moves was from any position on the board.  I'm sure that there are many
>>positions which do not require the full 34 moves and a few which would.  Which
>>positions would require the 34 moves, I don't know.
>>
>>I haven't seen any documentation on this in recent books but back in the 70's
>>there was quite a bit available.  Unfortunately, I don't have any of those old
>>books around.  I think the basic mates were as follows:
>>
>>KQ v K - 9 moves
>>KR v K - 12 moves
>>KBB v K - 20 moves
>>KNB v K - 34 moves
>>
>>Again, from any position on the board, mate could be accomplished within the
>>number of moves above with best play.
>
>Ok...Perhaps you're thinking that 34 moves (68 ply) is surpassing the 50 move
>rule, but it isn't.  50 moves (100 ply) is needed for that.  There are no KBN
>vs. K endings that take so many.

Jeremiah,

KarinsDad's reply to this post is correct.  At one time I believe there was a
rule which allowed you to exceed the 50 move rule in the case of a known forced
mate where with best play twice the number of moves exceeded the 50 (100 ply).
The KBN ending fits this scenario.

I have posted a query to the USCF concerning this.  Perhaps they will be able to
verify it or not.

Steve



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