unique losing positions in endgame databases

[Rein Halbersma]

Spoiler:

1403 3.183.280.592 21.081.806.976 1

This was an example of a unique losing position in the 1403 database over at the 8 pc database thread viewtopic.php?f=53&t=2926&start=13. Michel Grimminck's website http://www.xs4all.nl/~mdgsoft/draughts/stats/index.html shows a few more databases with unique losing (non-capture) positions. Below my attempt to reproduce them.

Spoiler:

1110: v 64.099 (86.8%) 9.776 (13.2%) 1 (0.0%)

Spoiler:

1220: v 17.867.630 (88.5%) 2.327.578 (11.5%) 1 (0.0%)

Spoiler:

3110: v 19.510.908 (100.0%) 3.809 (0.0%) 1 (0.0%)
3101: v 20.716.598 (91.8%) 1.844.239 (8.2%) 1 (0.0%)

Spoiler:

4110: v 277.875.483 (100.0%) 191 1
4101: v 305.938.111 (99.2%) 2.481.538 1

Spoiler:

2301: v 769.382.382 (99.9%) 1.154.417 1

[Rein Halbersma]

0420: v 192.356.836 (99.9%) 277.363 1

The above diagram is left as an exercise for the reader: place 4 white kings and 2 black man on the board. White to move loses in 2 moves!

[jj]

Hi Rein,

Nice puzzle. Is this the solution?

Spoiler:

1.14x5 19x46 2.5-X 46x5

Jan-Jaap

[Rein Halbersma]

Hi Rein,

Nice puzzle. Is this the solution?

Spoiler:

1.14x5 19x46 2.5-X 46x5

Jan-Jaap

Yes, congratulations! DId you solve it by hand or did you search your own databases?

[jj]

Yes, congratulations! DId you solve it by hand or did you search your own databases?

By hand. It is a nice logic puzzle!

BTW, do you agree that this position is impossible to reach, since no black move can lead to this position?

[ildjarn]

There is a unique losing position with 2K vs 2P which is legal.

[Rein Halbersma]

There is a unique losing position with 2K vs 2P which is legal.

Ah I missed this one from the stats, I only looked at the non-capture positions column!

Spoiler:

last black move: 31-37

[Rein Halbersma]

Just to be complete, there is also a unique 1P vs 1K winning solution

Spoiler:

[BertTuyt]

Rein, are you sure the last 2 positions are correct.
White still can move with the 2 white man.
In the 2 positions white can even win.
If at least the international Draughts rules are applied....

Bert

[BertTuyt]

Think the diagram is upside down

Bert

[Rein Halbersma]

Think the diagram is upside down

Bert

Thanks Bert, I indeed had the position flipped. The other one was also flipped but is then equal to one above it. The original post is now modified.

[Rein Halbersma]

Put 1 white man, 3 white kings and 2 black men on the board in such a way that white to move cannot capture and can only draw under the Killer rules!

Hint: in Killer draughts a king has to stop immediately after the last captured piece, if and only if that piece was a king. This means that 2 kings can catch an enemy king. It is therefore not enough for black to get 1 or even 2 kings in order to make a draw in this endgame.

[steenslag]

0420: v 192.356.836 (99.9%) 277.363 1

The above diagram is left as an exercise for the reader: place 4 white kings and 2 black man on the board. White to move loses in 2 moves!

see: viewtopic.php?p=18015#p18015

[ildjarn]

Put 1 white man, 3 white kings and 2 black men on the board in such a way that white to move cannot capture and can only draw under the Killer rules!

Hint: in Killer draughts a king has to stop immediately after the last captured piece, if and only if that piece was a king. This means that 2 kings can catch an enemy king. It is therefore not enough for black to get 1 or even 2 kings in order to make a draw in this endgame.

I've been thinking about this, and can't think of anything. Do you have a hint?

[Rein Halbersma]

Put 1 white man, 3 white kings and 2 black men on the board in such a way that white to move cannot capture and can only draw under the Killer rules!

Hint: in Killer draughts a king has to stop immediately after the last captured piece, if and only if that piece was a king. This means that 2 kings can catch an enemy king. It is therefore not enough for black to get 1 or even 2 kings in order to make a draw in this endgame.

I've been thinking about this, and can't think of anything. Do you have a hint?

Well, I have to confess that I haven't solved this one myself yet! And I also don't know for sure if the Killer rule is essential here, because Michel's site doesn't contain the non-capture statistics for this particular endgame for international draughts (it does for Killer draughts).

Michel, can you help us out here?