Black is in a stalemate position.

competition/games/chess/stalemate.moves New

New entry, edited from material collected for the archive and not yet in a released version.

Problem

Black is in a stalemate position.  How many moves can White's next move
allow Black?

Variation: White's next move will put Black in stalemate.  Find the
position with the maximum number of Black moves (before White's move).

[ Editor: problem statement reconstructed from the postings. ]

Show solution

In article <3am4tn$18q@galileo.polito.it>
mauceri@monviso.alpcom.it (Claudio Mauceri) writes:

>a lot of time ago, I don't remember well who and when, the following
>chess problem has been posted:
>
>Black is in stalemate position.
>How many moves the next white's move can allow to black?

I would be interested to know who originated this; it (as well
as the follow-up you give below) is a neat puzzle -- a natural
and apparently new question with a surprisingly large answer.

>We have worked a bit on this task, and
>we have found the following position:
>
>White Ka6,Bd1,f8,Rh4; Black Ka4,Bd4,Rb3,Pd2,h5

[presumably "f8" is Bf8 or Qf8]

>in which the move 1.Bg4 grant to black 32 moves.
>Now, can anyone do better? Good luck!

I suspect this is best possible but I do not have a proof.

>In add, especially for who have posted this task, I would like to propose
>the following variation:
>
>White's next move will put black in stalemate.
>Find the position with the maximum number of black's move.
>
>For this task we have found a position that allow to black 50 moves.

Presumably some version of the following:

+-----------------+
| . _ . _ . _ . _ |
| _ . _ . _ . _ . |
| . _ . _ . _ . _ |
| _ . _ . q . _ . |
| . _ . _ . _ . K |
| _ . _ . _ . r B |
| R B p _ . _ . k |
| _ Q _ R _ . _ . |
|_________________|

in which 1.Bxe5, stalemate, deprives Black of 24+14+12=50 moves.
I found several variations on this idea (e.g. add a Black pawn on a3)
but no improvements.

-- Noam D. Elkies <elkies@zariski.harvard.edu>