[Retros] Shortest SPGs ending in mate

[Francois Labelle]

Christoph Fieberg wrote:


> Record for knight already was at 4.5 moves found by myself.


Of course to claim new records I'm dependent on having an up-to-date
summary of the current records. I think that Richard's summary was
correct, and that you're simply not reading the notation correctly.


> >Mate by knight (3.0):

> >rc: G"oran Wicklund, retros mailing list, october 1996

> >     (5.5): 1.Nf3 e6 2.Ne5 Ne7 3.Nxd7 e5 4.Nxf8 Bd7 5.Ne6 Rf8 6.Nxg7#

> >     Francois Labelle

> >     (4.5): 1.d4 e6 2.Bg5 Ba3 3.Nxa3 Qe7 4.Nb5 Qf8 5.Nxc7#

>

> SPG in 4,5 moves - Christoph Fieberg - Retro mailing list 4.10.2002

> 1r1qkb1r/pp1pnppp/2nN4/2p5/8/8/PPPPPPPP/R1BQKBNR b KQk - 0 5

> 1.Nc3 c5 2.Nd5 Nc6 3.Nxe7 Rb8 4.Nxc8 Nge7 5.Nd6#


The easy-to-miss "rc" means "mating move Requires Capturing". Your SPG in
4.5 moves doesn't end with a capture.

Similarly, my improvement to "Mate by pawn promoting to queen" was for the
"wc" subcategory (Without Capturing in the mating move), etc.

Taking into account the two-letter codes, are my claims to record now ok?


OTHER POINTS OF DISCUSSION

I was expecting any follow-up discussion to be about these two points.

1- It's amusing that my computer chose to use a promoted knight for
"one-sided mate by knight (dc)", so the category should probably be
renamed "mate by non-promoted knight" since we already have "mate by
promoted knight".


| Mate by knight:

| dc: open

|     Francois Labelle

|     (11): 1.c4 2.c5 3.c6 4.cxb7 5.bxa8=N 6.Nb6 7.Nxd7 8.Nxb8 9.Nd7

| 10.Qa4 11.Nf6#


2- My improvement to "one-sided mate by bishop (wc)" is a discovery
checkmate, and it's open to debate whether that's acceptable.


| Mate by bishop:

| wc: Juha M. Saukkola & Gianni Donati, retros mailing list, october 1996

|     (10): 1.a4 2.Ra3 3.Rf3 4.Rxf7 5.Rf3 6.Rc3 7.e3 8.Bd3 9.Bxh7 10.Bg6#

|     Francois Labelle

|     ( 9): 1.h4 2.Rh3 3.Rc3 4.d3 5.Bf4 6.Bxc7 7.Bxd8 8.Rxc8 9.Bc7#


The question is: what is meant by "mate by bishop"? The condition on the
last (checkmating) move that I used is simply:

"The stated piece is played."

But I have the feeling most of you mean something along the lines:

"The stated piece attacks the enemy king, except if the piece is the king
then the condition is that the stated piece is played. [Insert possible
condition that the stated piece must be played in all cases.] [Insert
possible condition forbidding double checkmate.]"

You guys work by recognizing a "mate by bishop" when you see one, but I
need a precise definition ahead of time so I can tell my computer what to
look for.

	Francois