[Retros] Fastest selfmates in 1?

François Labelle flab at wismuth.com
Sat Dec 12 14:06:21 EST 2020


The results are in.

My computer found 60 positions after 5.5 moves where mate is forced 
next. Adding the number of ways these positions can be reached, I get a 
total of 6401 games. As some people know, for me, position = diagram + 
castling info + ep info, but in this case it turns out that the 
distinction doesn't matter. There are 60 diagrams as well.

I manually reordered the computer output to group similar positions 
together. It's possible that the grouping I made is imperfect, so please 
someone review it.

Below are the 60 positions in forsyth notation, and after the colon is 
the number of games leading to that position in 5.5 moves.

# Pim Blijlevens 1
rnbq1b1r/pppp1ppp/6kn/3Np3/5PPN/8/PPPPP2P/R1BQKB1R : 69
rnbq1b1r/pppp1ppp/4p1kn/3N4/5PPN/8/PPPPP2P/R1BQKB1R : 69
rnbq1b1r/pppp1ppp/4p1kn/8/1P3PPN/8/PBPPP2P/RN1QKB1R : 69
rnbq1b1r/pppp1ppp/4p1kn/8/5PPN/1P6/PBPPP2P/RN1QKB1R : 69

# Pim Blijlevens 2
r1bqkb1r/ppppp2p/5n2/5ppQ/3nP3/6KN/PPPP1PPP/RNB2B1R : 111
r1bqkb1r/ppppp2p/5n2/5ppQ/3n4/4P1KN/PPPP1PPP/RNB2B1R : 111
rn1qkb1r/pbppp2p/1p3n2/5ppQ/8/4P1KN/PPPP1PPP/RNB2B1R : 111
rn1qkb1r/pbppp2p/5n2/1p3ppQ/8/4P1KN/PPPP1PPP/RNB2B1R : 111

# Sasho Kalajdzievski
rnbqkbnr/1pppp3/p7/5p1Q/4Pp2/7K/PPPP2PP/RNB2BNR : 222
rnbqkbnr/1pppp3/p7/5p1Q/5p2/4P2K/PPPP2PP/RNB2BNR : 222
rnbqkbnr/1pppp3/8/p4p1Q/4Pp2/7K/PPPP2PP/RNB2BNR : 222
rnbqkbnr/1pppp3/8/p4p1Q/5p2/4P2K/PPPP2PP/RNB2BNR : 222
rnbqkbnr/p1ppp3/1p6/5p1Q/4Pp2/7K/PPPP2PP/RNB2BNR : 222
rnbqkbnr/p1ppp3/1p6/5p1Q/5p2/4P2K/PPPP2PP/RNB2BNR : 222
rnbqkbnr/p1ppp3/8/1p3p1Q/4Pp2/7K/PPPP2PP/RNB2BNR : 222
rnbqkbnr/p1ppp3/8/1p3p1Q/5p2/4P2K/PPPP2PP/RNB2BNR : 222
rnbqkbnr/pp1pp3/2p5/5p1Q/4Pp2/7K/PPPP2PP/RNB2BNR : 222
rnbqkbnr/pp1pp3/2p5/5p1Q/5p2/4P2K/PPPP2PP/RNB2BNR : 222
rnbqkbnr/pp1pp3/8/2p2p1Q/4Pp2/7K/PPPP2PP/RNB2BNR : 222
rnbqkbnr/pp1pp3/8/2p2p1Q/5p2/4P2K/PPPP2PP/RNB2BNR : 222
r1bqkbnr/ppppp3/2n5/5p1Q/4Pp2/7K/PPPP2PP/RNB2BNR : 222
r1bqkbnr/ppppp3/2n5/5p1Q/5p2/4P2K/PPPP2PP/RNB2BNR : 222
r1bqkbnr/ppppp3/n7/5p1Q/4Pp2/7K/PPPP2PP/RNB2BNR : 222
r1bqkbnr/ppppp3/n7/5p1Q/5p2/4P2K/PPPP2PP/RNB2BNR : 222
rnbqkbnr/ppppp3/8/5p1Q/4Pp2/7K/PPPP2PP/RNB2BNR : 314
rnbqkbnr/ppppp3/8/5p1Q/5p2/4P2K/PPPP2PP/RNB2BNR : 314
rnbqkb1r/ppppp3/8/5ppQ/4n3/4P2K/PPPP1PPP/RNB2BNR : 30
rnbqkb1r/ppppp3/8/5ppQ/4n3/7K/PPPP1PPP/RNB2BNR : 30
rnbqkb1r/ppppp3/8/5ppQ/4nP2/4P2K/PPPP2PP/RNB2BNR : 130
rnbqkb1r/ppppp3/8/5ppQ/4nP2/7K/PPPP2PP/RNB2BNR : 108

# Noam Elkies
1rbqkbnr/p1Nppppp/8/8/8/1nKP4/PPP1PPPP/R1BQ1BNR : 396
1rbqkbnr/p1Nppppp/8/8/8/2KP1n2/PPP1PPPP/R1BQ1BNR : 264

# group 5
r1bq1bnr/pppnkppp/8/4Q3/3pP3/3K4/PPPPBPPP/RNB3NR : 40
r1bq1bnr/pppnkppp/8/4Q3/3pP3/3K4/PPPPNPPP/RNB2B1R : 40

# group 6
r1bqkb1r/ppppn2p/2n1p3/5pKQ/4P3/8/PPPP1PPP/RNB2BNR : 27
r1bqkb1r/ppppn2p/2n1p3/5pKQ/8/4P3/PPPP1PPP/RNB2BNR : 21
r1bqkb1r/ppppn2p/n3p3/5pKQ/4P3/8/PPPP1PPP/RNB2BNR : 27
r1bqkb1r/ppppn2p/n3p3/5pKQ/8/4P3/PPPP1PPP/RNB2BNR : 21
r1bqkbnr/ppppn2p/4p3/5pKQ/4P3/8/PPPP1PPP/RNB2BNR : 12
r1bqkbnr/ppppn2p/4p3/5pKQ/8/4P3/PPPP1PPP/RNB2BNR : 10
rnbqkb1r/1pppn2p/4p3/p4pKQ/4P3/8/PPPP1PPP/RNB2BNR : 27
rnbqkb1r/1pppn2p/4p3/p4pKQ/8/4P3/PPPP1PPP/RNB2BNR : 21
rnbqkb1r/1pppn2p/p3p3/5pKQ/4P3/8/PPPP1PPP/RNB2BNR : 27
rnbqkb1r/1pppn2p/p3p3/5pKQ/8/4P3/PPPP1PPP/RNB2BNR : 21
rnbqkb1r/p1ppn2p/1p2p3/5pKQ/4P3/8/PPPP1PPP/RNB2BNR : 27
rnbqkb1r/p1ppn2p/1p2p3/5pKQ/8/4P3/PPPP1PPP/RNB2BNR : 21
rnbqkb1r/p1ppn2p/4p3/1p3pKQ/4P3/8/PPPP1PPP/RNB2BNR : 27
rnbqkb1r/p1ppn2p/4p3/1p3pKQ/8/4P3/PPPP1PPP/RNB2BNR : 21
rnbqkb1r/pp1pn2p/2p1p3/5pKQ/4P3/8/PPPP1PPP/RNB2BNR : 27
rnbqkb1r/pp1pn2p/2p1p3/5pKQ/8/4P3/PPPP1PPP/RNB2BNR : 21
rnbqkb1r/pp1pn2p/4p3/2p2pKQ/4P3/8/PPPP1PPP/RNB2BNR : 27
rnbqkb1r/pp1pn2p/4p3/2p2pKQ/8/4P3/PPPP1PPP/RNB2BNR : 21
rnbqkb1r/ppppn2p/4p3/5pKQ/4P3/8/PPPP1PPP/RNB2BNR : 14
rnbqkb1r/ppppn2p/4p3/5pKQ/8/4P3/PPPP1PPP/RNB2BNR : 11

# group 7
rnb2bnr/pppp1ppp/2Q5/4pkq1/6P1/4PK2/PPPP1P1P/RNB2BNR : 1
rnb2bnr/pppp1ppp/7Q/4pk2/6Pq/4PK2/PPPP1P1P/RNB2BNR : 5
rnb2bnr/pppp1ppp/7Q/4pkq1/6P1/4PK2/PPPP1P1P/RNB2BNR : 5
rnb2bnr/pppp1ppp/Q7/4pkq1/6P1/4PK2/PPPP1P1P/RNB2BNR : 5

# group 8
rnbqkb1r/ppppp1pp/5pB1/8/8/4Pn2/PPPP1PP1/RNBQ1R1K : 12
rnbqkb1r/ppppp1pp/5pB1/8/8/4Pn2/PPPPNPP1/RNBQ1R1K : 4

As the next step, maybe someone (Noam?) can go through this list and 
simplify the exposition by choosing a few representative diagrams and 
describing the variations in text? To help with that, I'm attaching a 
file containing the same list in ASCII diagrams. Make sure to view it in 
a fixed font like Courier.

Attentive people will notice that there is exactly one unique proof game 
in the list (a diagram with only 1 solution):

1.e3 e5 2.Qf3 Ke7 3.Ke2 Ke6 4.Qc6+ Kf5 5.Kf3 Qg5 6.g4+ (6...Qxg4#)

This is an improvement over the PG in 6.0 by James and Noam.

     François
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# Pim Blijlevens 1
 _________________ _________________ _________________ _________________ 
|                 |                 |                 |                 |
| r n b q . b . r | r n b q . b . r | r n b q . b . r | r n b q . b . r |
| p p p p . p p p | p p p p . p p p | p p p p . p p p | p p p p . p p p |
| . . . . . . k n | . . . . p . k n | . . . . p . k n | . . . . p . k n |
| . . . N p . . . | . . . N . . . . | . . . . . . . . | . . . . . . . . |
| . . . . . P P N | . . . . . P P N | . P . . . P P N | . . . . . P P N |
| . . . . . . . . | . . . . . . . . | . . . . . . . . | . P . . . . . . |
| P P P P P . . P | P P P P P . . P | P B P P P . . P | P B P P P . . P |
| R . B Q K B . R | R . B Q K B . R | R N . Q K B . R | R N . Q K B . R |
|_________________|_________________|_________________|_________________|

# Pim Blijlevens 2
 _________________ _________________ _________________ _________________ 
|                 |                 |                 |                 |
| r . b q k b . r | r . b q k b . r | r n . q k b . r | r n . q k b . r |
| p p p p p . . p | p p p p p . . p | p b p p p . . p | p b p p p . . p |
| . . . . . n . . | . . . . . n . . | . p . . . n . . | . . . . . n . . |
| . . . . . p p Q | . . . . . p p Q | . . . . . p p Q | . p . . . p p Q |
| . . . n P . . . | . . . n . . . . | . . . . . . . . | . . . . . . . . |
| . . . . . . K N | . . . . P . K N | . . . . P . K N | . . . . P . K N |
| P P P P . P P P | P P P P . P P P | P P P P . P P P | P P P P . P P P |
| R N B . . B . R | R N B . . B . R | R N B . . B . R | R N B . . B . R |
|_________________|_________________|_________________|_________________|

# Sasho Kalajdzievski
 _________________ _________________ _________________ _________________ 
|                 |                 |                 |                 |
| r n b q k b n r | r n b q k b n r | r n b q k b n r | r n b q k b n r |
| . p p p p . . . | . p p p p . . . | . p p p p . . . | . p p p p . . . |
| p . . . . . . . | p . . . . . . . | . . . . . . . . | . . . . . . . . |
| . . . . . p . Q | . . . . . p . Q | p . . . . p . Q | p . . . . p . Q |
| . . . . P p . . | . . . . . p . . | . . . . P p . . | . . . . . p . . |
| . . . . . . . K | . . . . P . . K | . . . . . . . K | . . . . P . . K |
| P P P P . . P P | P P P P . . P P | P P P P . . P P | P P P P . . P P |
| R N B . . B N R | R N B . . B N R | R N B . . B N R | R N B . . B N R |
|_________________|_________________|_________________|_________________|
|                 |                 |                 |                 |
| r n b q k b n r | r n b q k b n r | r n b q k b n r | r n b q k b n r |
| p . p p p . . . | p . p p p . . . | p . p p p . . . | p . p p p . . . |
| . p . . . . . . | . p . . . . . . | . . . . . . . . | . . . . . . . . |
| . . . . . p . Q | . . . . . p . Q | . p . . . p . Q | . p . . . p . Q |
| . . . . P p . . | . . . . . p . . | . . . . P p . . | . . . . . p . . |
| . . . . . . . K | . . . . P . . K | . . . . . . . K | . . . . P . . K |
| P P P P . . P P | P P P P . . P P | P P P P . . P P | P P P P . . P P |
| R N B . . B N R | R N B . . B N R | R N B . . B N R | R N B . . B N R |
|_________________|_________________|_________________|_________________|
|                 |                 |                 |                 |
| r n b q k b n r | r n b q k b n r | r n b q k b n r | r n b q k b n r |
| p p . p p . . . | p p . p p . . . | p p . p p . . . | p p . p p . . . |
| . . p . . . . . | . . p . . . . . | . . . . . . . . | . . . . . . . . |
| . . . . . p . Q | . . . . . p . Q | . . p . . p . Q | . . p . . p . Q |
| . . . . P p . . | . . . . . p . . | . . . . P p . . | . . . . . p . . |
| . . . . . . . K | . . . . P . . K | . . . . . . . K | . . . . P . . K |
| P P P P . . P P | P P P P . . P P | P P P P . . P P | P P P P . . P P |
| R N B . . B N R | R N B . . B N R | R N B . . B N R | R N B . . B N R |
|_________________|_________________|_________________|_________________|
|                 |                 |                 |                 |
| r . b q k b n r | r . b q k b n r | r . b q k b n r | r . b q k b n r |
| p p p p p . . . | p p p p p . . . | p p p p p . . . | p p p p p . . . |
| . . n . . . . . | . . n . . . . . | n . . . . . . . | n . . . . . . . |
| . . . . . p . Q | . . . . . p . Q | . . . . . p . Q | . . . . . p . Q |
| . . . . P p . . | . . . . . p . . | . . . . P p . . | . . . . . p . . |
| . . . . . . . K | . . . . P . . K | . . . . . . . K | . . . . P . . K |
| P P P P . . P P | P P P P . . P P | P P P P . . P P | P P P P . . P P |
| R N B . . B N R | R N B . . B N R | R N B . . B N R | R N B . . B N R |
|_________________|_________________|_________________|_________________|
|                 |                 |                 |                 |
| r n b q k b n r | r n b q k b n r | r n b q k b . r | r n b q k b . r |
| p p p p p . . . | p p p p p . . . | p p p p p . . . | p p p p p . . . |
| . . . . . . . . | . . . . . . . . | . . . . . . . . | . . . . . . . . |
| . . . . . p . Q | . . . . . p . Q | . . . . . p p Q | . . . . . p p Q |
| . . . . P p . . | . . . . . p . . | . . . . n . . . | . . . . n . . . |
| . . . . . . . K | . . . . P . . K | . . . . P . . K | . . . . . . . K |
| P P P P . . P P | P P P P . . P P | P P P P . P P P | P P P P . P P P |
| R N B . . B N R | R N B . . B N R | R N B . . B N R | R N B . . B N R |
|_________________|_________________|_________________|_________________|
|                 |                 |
| r n b q k b . r | r n b q k b . r |
| p p p p p . . . | p p p p p . . . |
| . . . . . . . . | . . . . . . . . |
| . . . . . p p Q | . . . . . p p Q |
| . . . . n P . . | . . . . n P . . |
| . . . . P . . K | . . . . . . . K |
| P P P P . . P P | P P P P . . P P |
| R N B . . B N R | R N B . . B N R |
|_________________|_________________|

# Noam Elkies
 _________________ _________________ 
|                 |                 |
| . r b q k b n r | . r b q k b n r |
| p . N p p p p p | p . N p p p p p |
| . . . . . . . . | . . . . . . . . |
| . . . . . . . . | . . . . . . . . |
| . . . . . . . . | . . . . . . . . |
| . n K P . . . . | . . K P . n . . |
| P P P . P P P P | P P P . P P P P |
| R . B Q . B N R | R . B Q . B N R |
|_________________|_________________|

# group 5
 _________________ _________________ 
|                 |                 |
| r . b q . b n r | r . b q . b n r |
| p p p n k p p p | p p p n k p p p |
| . . . . . . . . | . . . . . . . . |
| . . . . Q . . . | . . . . Q . . . |
| . . . p P . . . | . . . p P . . . |
| . . . K . . . . | . . . K . . . . |
| P P P P B P P P | P P P P N P P P |
| R N B . . . N R | R N B . . B . R |
|_________________|_________________|

# group 6
 _________________ _________________ _________________ _________________ 
|                 |                 |                 |                 |
| r . b q k b . r | r . b q k b . r | r . b q k b . r | r . b q k b . r |
| p p p p n . . p | p p p p n . . p | p p p p n . . p | p p p p n . . p |
| . . n . p . . . | . . n . p . . . | n . . . p . . . | n . . . p . . . |
| . . . . . p K Q | . . . . . p K Q | . . . . . p K Q | . . . . . p K Q |
| . . . . P . . . | . . . . . . . . | . . . . P . . . | . . . . . . . . |
| . . . . . . . . | . . . . P . . . | . . . . . . . . | . . . . P . . . |
| P P P P . P P P | P P P P . P P P | P P P P . P P P | P P P P . P P P |
| R N B . . B N R | R N B . . B N R | R N B . . B N R | R N B . . B N R |
|_________________|_________________|_________________|_________________|
|                 |                 |                 |                 |
| r . b q k b n r | r . b q k b n r | r n b q k b . r | r n b q k b . r |
| p p p p n . . p | p p p p n . . p | . p p p n . . p | . p p p n . . p |
| . . . . p . . . | . . . . p . . . | . . . . p . . . | . . . . p . . . |
| . . . . . p K Q | . . . . . p K Q | p . . . . p K Q | p . . . . p K Q |
| . . . . P . . . | . . . . . . . . | . . . . P . . . | . . . . . . . . |
| . . . . . . . . | . . . . P . . . | . . . . . . . . | . . . . P . . . |
| P P P P . P P P | P P P P . P P P | P P P P . P P P | P P P P . P P P |
| R N B . . B N R | R N B . . B N R | R N B . . B N R | R N B . . B N R |
|_________________|_________________|_________________|_________________|
|                 |                 |                 |                 |
| r n b q k b . r | r n b q k b . r | r n b q k b . r | r n b q k b . r |
| . p p p n . . p | . p p p n . . p | p . p p n . . p | p . p p n . . p |
| p . . . p . . . | p . . . p . . . | . p . . p . . . | . p . . p . . . |
| . . . . . p K Q | . . . . . p K Q | . . . . . p K Q | . . . . . p K Q |
| . . . . P . . . | . . . . . . . . | . . . . P . . . | . . . . . . . . |
| . . . . . . . . | . . . . P . . . | . . . . . . . . | . . . . P . . . |
| P P P P . P P P | P P P P . P P P | P P P P . P P P | P P P P . P P P |
| R N B . . B N R | R N B . . B N R | R N B . . B N R | R N B . . B N R |
|_________________|_________________|_________________|_________________|
|                 |                 |                 |                 |
| r n b q k b . r | r n b q k b . r | r n b q k b . r | r n b q k b . r |
| p . p p n . . p | p . p p n . . p | p p . p n . . p | p p . p n . . p |
| . . . . p . . . | . . . . p . . . | . . p . p . . . | . . p . p . . . |
| . p . . . p K Q | . p . . . p K Q | . . . . . p K Q | . . . . . p K Q |
| . . . . P . . . | . . . . . . . . | . . . . P . . . | . . . . . . . . |
| . . . . . . . . | . . . . P . . . | . . . . . . . . | . . . . P . . . |
| P P P P . P P P | P P P P . P P P | P P P P . P P P | P P P P . P P P |
| R N B . . B N R | R N B . . B N R | R N B . . B N R | R N B . . B N R |
|_________________|_________________|_________________|_________________|
|                 |                 |                 |                 |
| r n b q k b . r | r n b q k b . r | r n b q k b . r | r n b q k b . r |
| p p . p n . . p | p p . p n . . p | p p p p n . . p | p p p p n . . p |
| . . . . p . . . | . . . . p . . . | . . . . p . . . | . . . . p . . . |
| . . p . . p K Q | . . p . . p K Q | . . . . . p K Q | . . . . . p K Q |
| . . . . P . . . | . . . . . . . . | . . . . P . . . | . . . . . . . . |
| . . . . . . . . | . . . . P . . . | . . . . . . . . | . . . . P . . . |
| P P P P . P P P | P P P P . P P P | P P P P . P P P | P P P P . P P P |
| R N B . . B N R | R N B . . B N R | R N B . . B N R | R N B . . B N R |
|_________________|_________________|_________________|_________________|

# group 7
 _________________ _________________ _________________ _________________ 
|                 |                 |                 |                 |
| r n b . . b n r | r n b . . b n r | r n b . . b n r | r n b . . b n r |
| p p p p . p p p | p p p p . p p p | p p p p . p p p | p p p p . p p p |
| . . Q . . . . . | . . . . . . . Q | . . . . . . . Q | Q . . . . . . . |
| . . . . p k q . | . . . . p k . . | . . . . p k q . | . . . . p k q . |
| . . . . . . P . | . . . . . . P q | . . . . . . P . | . . . . . . P . |
| . . . . P K . . | . . . . P K . . | . . . . P K . . | . . . . P K . . |
| P P P P . P . P | P P P P . P . P | P P P P . P . P | P P P P . P . P |
| R N B . . B N R | R N B . . B N R | R N B . . B N R | R N B . . B N R |
|_________________|_________________|_________________|_________________|

# group 8
 _________________ _________________ 
|                 |                 |
| r n b q k b . r | r n b q k b . r |
| p p p p p . p p | p p p p p . p p |
| . . . . . p B . | . . . . . p B . |
| . . . . . . . . | . . . . . . . . |
| . . . . . . . . | . . . . . . . . |
| . . . . P n . . | . . . . P n . . |
| P P P P . P P . | P P P P N P P . |
| R N B Q . R . K | R N B Q . R . K |
|_________________|_________________|


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