See also Amenor wins World 6x6 championships!
This is the form in which the solutions were stored in Paderborn in 1993. There are
more details on the solution from the standard starting position in the
July 1993 issue of the British Othello Federation's newsletter. This
article ("Amenor wins World 6x6 championships!") is also available (see link above).
Briefly, the first of these solutions took 2 weeks CPU time on our SGI,
and required the generation of about 40,000,000,000 positions. The second
took five weeks CPU time, and required the searching of about
100,000,000,000 positions.
I used a brute force alpha-beta search, with moves ordered by short
midgame searches (using my program's midgame evaluator which is not too
bad). The process used only 70K of memory! A bigger memory hog would have
solved the problem faster but might have upset my colleagues.
It helped a lot to guess that the results would be close as my endgame
analyser is comparatively slow if it is not working in a small window.
Joel Feinstein
************************************************************************
The solution for the 6x6 Othello board.
Thanks to Joel F. Feinstein and MODOT.
A B C D E F G H
1 | | | | | | | | | 1
2 | | | | | | | | | 2
3 | | | | | | | | | 3
4 | | | |()|##| | | | 4
5 | | | |##|()| | | | 5
6 | | | | | | | | | 6
7 | | | | | | | | | 7
8 | | | | | | | | | 8
A B C D E F G H
-> ##
A B C D E F G H
1 | | | | | | | | | 1
2 | |28| 9| 8| 7|31|32| | 2
3 | |22|14| 1| 4|17|16| | 3
4 | |27|13|()|##| 6|15| | 4
5 | |19| 2|##|()| 5|12| | 5
6 | |24|23| 3|10|26|29| | 6
7 | |21|18|20|11|25|30| | 7
8 | | | | | | | | | 8
A B C D E F G H
1: d3 2: c5
3: d6 4: e3
5: f5 6: f4
7: e2 8: d2
9: c2 10: e6
11: e7 12: g5
13: c4 14: c3
15: g4 16: g3
17: f3 18: c7
19: b5 20: d7
21: b7 22: b3
23: c6 24: b6
25: f7 26: f6
27: b4 28: b2
29: g6 30: g7
31: pa 32: f2
33: g2
A B C D E F G H
1 | | | | | | | | | 1
2 | |()|()|()|()|()|##| | 2
3 | |()|()|##|()|##|()| | 3
4 | |##|##|()|##|()|()| | 4
5 | |##|##|##|()|()|()| | 5
6 | |()|()|##|##|()|()| | 6
7 | |##|##|##|##|##|()| | 7
8 | | | | | | | | | 8
A B C D E F G H
##:16 - ():20
The solution for the 6x6 Othello board with Reversi start position.
Thanks to Joel F. Feinstein and MODOT.
A B C D E F G H
1 | | | | | | | | | 1
2 | | | | | | | | | 2
3 | | | | | | | | | 3
4 | | | |##|()| | | | 4
5 | | | |##|()| | | | 5
6 | | | | | | | | | 6
7 | | | | | | | | | 7
8 | | | | | | | | | 8
A B C D E F G H
-> ##
A B C D E F G H
1 | | | | | | | | | 1
2 | |21|20|19|18|17|28| | 2
3 | |32|31|14|12|22|26| | 3
4 | |15|10|##|()| 1|27| | 4
5 | |11| 2|##|()| 4|13| | 5
6 | |24| 9| 3| 5|29|30| | 6
7 | |16|23| 6| 7| 8|25| | 7
8 | | | | | | | | | 8
A B C D E F G H
1: f4 2: c5
3: d6 4: f5
5: e6 6: d7
7: e7 8: f7
9: c6 10: c4
11: b5 12: e3
13: g5 14: d3
15: b4 16: b7
17: f2 18: e2
19: d2 20: c2
21: b2 22: f3
23: c7 24: b6
25: g7 26: g3
27: g4 28: g2
29: f6 30: g6
31: pa 32: c3
33: b3
A B C D E F G H
1 | | | | | | | | | 1
2 | |##|##|##|##|##|()| | 2
3 | |##|()|()|()|()|()| | 3
4 | |##|##|()|()|##|()| | 4
5 | |##|()|##|()|()|()| | 5
6 | |()|()|()|##|()|()| | 6
7 | |()|##|##|##|##|##| | 7
8 | | | | | | | | | 8
A B C D E F G H
##:17 - ():19