[Retros] Shortest # SPGs - Category II complete!

[fieberg at gcr.com]

New entries (*):

- 2 SPG from Ulrich Ring
# Ph2->B (6.5)
1.h4 d6 2.h5 Bf5 3.h6 e6 4.hg7: Be7 5.gh8:B Kf8 6.Rh7: Qe8 7.Bg7#

# ep-a/Ra1 (8.5)
1.a4 d6 2.a5 Bf5 3.Ra4 Bd3 4.ed3: Kd7 5.Qg4 Kc6 6.Dc8 Kb5 7.Qb8 Ka6 8.d4+
b5 9.ab6:ep#
First ep-entry!

- 1 SPG from Jens Guballa
# Pa2->B (6.5)
1.a4 c5 2.a5 Nc6 3.a6 Qa5 4.axb7 Qa2 5.bxc8=B Qxb1 6.Rxa7 Nd8 7.Bxd7#

- 1 SPG from Noam Elkies
Alternative for # Pa2->B (6.5)
1 a4 h5 2 a5 Rh6 3 a6 Re6 4 ab f6 5 b:a8=B Ba6 6 Be4 Bb5 7 Bg6#

- 2 SPGs from myself
Alternative for # Ph2 (4.5)
1.h4 g5 2.hxg5 f5 3.Rxh7 Nh6 4.g6 Nf7 5.gxf7#

# Pb2->B (7.5)
1.b4 a5 2.bxa5 b5 3.a6 Bb7 4.axb7 h5 5.bxa8B Rh6 6.Be4 Rc6 7.e3 f6 8.Bg6#
Hopefully this can be improved to 6.5!

Concerning category V I assume such SPGs are impossible (ep but discovered
checkmate not allowed).
Any thoughts?

Regards, CF


I) Checkmates

# P:
a2    SPG in 5,5 - CF 10/02
b2    SPG in 4,5 - CF 10/02
c2    SPG in 5,5 - CF 10/02
d2    SPG in 4,5 - CF 10/02
e2    SPG in 4,5 - CF 10/02
f2    SPG in 4,5 - NDE 10/02
g2    SPG in 4,5 - CF 10/02
h2    SPG in 4,5 - NDE 10/02, CF 10/02 (*)

# N:
b1    SPG in 4,5 - CF 10/02
g1    SPG in 4,5 - GF 6/96, NDE 10/02

# B:
c1    SPG in 4,5 - CF 10/02
f1    SPG in 3,5 - RS 5/96, CF 10/02

# R:
a1    SPG in 4,5 - GD 5/96, NDE 10/02
0-0-0 SPG in 7,5 - OH 6/96
h1    SPG in 4,5 - CF 10/02
0-0   SPG in 7,5 - OH 5/96

# Q:
d1    SPG in 2,5 - JMS 6/96, JH 6/96


II) Promotion checkmates

# ->Q:
a2    SPG in 4,5 - NDE 10/02
b2    SPG in 4,5 - JMS 10/02
c2    SPG in 4,5 - NDE 10/02
d2    SPG in 4,5 - JMS 10/02, UR 10/02
e2    SPG in 4,5 - GD 6/96, NDE 10/02
f2    SPG in 4,5 - NDE 10/02
g2    SPG in 4,5 - NDE 10/02
h2    SPG in 4,5 - NDE 10/02

# ->R:
a2    SPG in 4,5 - RS 5/96
b2    SPG in 4,5 - JMS 10/02
c2    SPG in 4,5 - NDE 10/02
d2    SPG in 4,5 - JMS 10/02
e2    SPG in 5,5 - CF 10/02
f2    SPG in 4,5 - NDE 10/02
g2    SPG in 5,5 - CF 10/02
h2    SPG in 4,5 - NDE 10/02

# ->B:
a2    SPG in 6,5 - JG 10/02 (*), NDE 10/02 (*)
b2    SPG in 7,5 - CF 10/02 (*)
c2    SPG in 5,5 - UR 10/02
d2    SPG in 5,5 - GF 5/96, NG 5/96, NDE 5/96
e2    SPG in 5,5 - UR 10/02
f2    SPG in 5,5 - CF 10/02
g2    SPG in 6,5 - CF 10/02
h2    SPG in 6,5 - UR 10/02 (*)

# ->N:
a2    SPG in 5,5 - NDE 10/02, UR 10/02
b2    SPG in 5,5 - CF 10/02
c2    SPG in 5,5 - NDE 10/02, UR 10/02
d2    SPG in 6,5 - UR 10/02
e2    SPG in 6,5 - CF 10/02
f2    SPG in 5,5 - NDE 10/02
g2    SPG in 5,5 - UR 10/02
h2    SPG in 5,5 - PRö 8/94, NDE 10/02


III) Discovered checkmates

# P/
Pc2/Qd1     SPG in 5,5 - NDE 10/02
Pe2/Qd1     SPG in 5,5 - NDE 10/02

# N/
Ng1/Rh1     SPG in 5,5 - NDE 10/02

# B/

# R/

# K/
Ke1/Qd1     SPG in 5,5 - NDE 10/02
Ke1/Bc1     SPG in 5,5 - CF 10/02


IV) Double checkmates

## P/
d2Q/Qd1     SPG in 5,5 - NDE 5/96
d2B/Qd1     SPG in 5,5 - NDE 5/96
e2N/Bc1     SPG in 8,5 - PRa 6/96

## N/
Ng1/Qd1     SPG in 5,5 - RS 6/96, NDE 10/02
Ng1/Bf1     SPG in 5,5 - NDE 10/02

## B/

## R/
Ra1/Qd1     SPG in 5,5 - NDE 10/02
Ra1/Bf1     SPG in 5,5 - NDE 10/02
Rh1/Qd1     SPG in 5,5 - NDE 10/02
Rh1/Bf1     SPG in 5,5 - NDE 10/02


V) En passant checkmates

ep-a
ep-b
ep-c
ep-d
ep-e
ep-f
ep-g
ep-h


VI) Discovered checkmates by en passant

# ep-a/
Ra1         SPG in 8,5 - UR 10/02 (*)

# ep-b/
# ep-c/
# ep-d/
# ep-e/
# ep-f/
# ep-g/
# ep-h/



CF = Christoph Fieberg
GD = Gianni Donati
GF = Göran Forslund
JG = Jens Guballa
JH = Joost de Heer
JMS = Juha M. Saukkola
NDE = Noam D. Elkies
NG = Norbert Geissler
OH = Olli Heimo
PRa = Paul Raican
PRö = Peter Rösler
RS = Richard Stanley
UR = Ulrich Ring


Categories for shortest checkmates in SPGs:

I) Checkmates
# Qd1 = Qd1 checkmates
# Pa2 = Pa2 checkmates
Pawns checkmate unpromoted. En passant moves belong to category V.
Castlings are special SPGs within this category.

II) Promotion checkmates
# Pa2->Q = Pa2 promotes to Q and this Q checkmates
The promotee may move. Discovered/double checkmates are not allowed.

III) Discovered checkmates
# Ke1/Qd1 = Ke1 makes the last move and discovers checkmating Qd1
# Pe2/Bf1 = Pe2 moves and discovers checkmating Bf1
Double checkmates are not allowed. En passant moves belong to category VI.

IV) Double checkmates
## Ra1/Qd1 = Ra1 moves with check and discovers Qd1 for doublecheck
## e2Q/Qd1 = Pe2 promotes to Q with check and discovers Qd1 for doublecheck

V) En passant checkmates
# ep-a = Pa2 checkmates en passant
Discovered checkmates are not allowed.

VI) Discovered checkmates by en passant
# ep-c/Qd1 = Pc2 moves en passant and discovers checkmating Qd1